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essential in bringing this information together. Again, if you've contributed to this FAQ, don't see your name listed, and
would like it listed, please contact me. No slight was intended, but with so much information from so many sources, it is
easy to lose a name. Also, if your email address has changed, it would be nice to update that.
Cheers,
Norm
What Are Hops?
Hops are cultivated flowers (humulus lupulus), green in color with yellow lupulin glands down between the petals, used
for preservative and flavoring characteristics in beer. The bitterness of the hop is used to balance the sweetness of the
malt, and the essential oils add a flavor/aroma which cannot be achieved by using any other plant. The hop plant is a
perennial spiraling vine which will grow in almost any climate given enough water and sunlight. It can climb either
string or poles and can reach heights of 40 feet. The flowers (or cones as they are often called) are usually dried before
use.
Bittering Compounds
One of the major contributions hops give to beer is a characteristic bitterness that provides a counterpoint to the rich
sweetness provided by the malt. This bitter flavor is extracted from the hops during the boil. It is during this time thatvirtually insoluble alpha acids are isomerized (rearranged without changing their composition) into more soluble and
stable iso-alpha acids, the main bittering substance in beer. Five different naturally occurring alpha acids have been
isolated from hops which are:
humulone
cohumulone
adhumulone
prehumulone
posthumulone
Although isomerized alpha acids are the biggest contributers, hops contain beta acids which also add bitterness to beer.The beta acids are similar to alpha acids both in structure and abundance. In contrast to alpha acids, it is not isomerized
beta acids that add bitterness, it is the oxidation products of the beta acids, which are bitter and soluble, that make their
presence felt. It should be noted that oxidized beta acids are not as bitter as isomerized alpha acids, and thus contribute
much less to the final bitterness of the beer.
Both the alpha and beta acids are very susceptible to oxidation, especially at temperatures above freezing. Theoretical
losses of alpha acids of up to 60% have been calculated for hops which are packaged and stored poorly. This is
important because once alpha acids have been oxidized they can no longer be isomerized into iso-alpha acid, thus
decreasing the hop's bittering potential. As stated above, oxidation components of beta acids contribute to bitterness, thus
the bittering potential of oxidized hops may not decrease as much as is commonly thought. This does not, in any way,
argue against storing hops well, since essential oils are dramatically and negatively altered by oxidation.
For these reasons, the "storageability" of each hop variety is sometimes provided, along with the alpha and beta acid
levels, by the hop broker. This parameter is usually given as a percentage of the alpha acids present after 6 months at
20C. Some good storage hops (usually high alpha acid) lose only 15-20% of their alpha acids: Cluster and Galena are
among the best. Most high quality aroma hops lose anywhere from 35-65% of their alpha acids unless anaerobic
conditions and cold storage (< 0C) are provided. This is why it is imperative for brewers to buy the freshest hops
available and store them in the coldest environment available, usually the freezer. It is also important to package the hops
properly, which means removing as much oxygen as possible and containing them in an oxygen barrier material.
Aroma and Flavor Compounds
Hops bring a lot more to beer than bitterness. The volatile oils, usually 0.5 - 3.0% (vol/wt) of the hop cone, are an
important flavor component of many types of beer. Brewers seeking to maximize hop flavor and aroma generally make
late kettle additions (0-15 min. before cooling) with high quality "aroma" hops. Dry hopping, i.e. the addition of hops to
the secondary fermenter or serving tank, is another way to add hop character to a beer although the aroma components
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Loose Hops
Advantages: They are the most natural form of the ingredient. They float, which is good for siphoning out from under,
and form a natural filter bed. When they are fresh, they beat all other forms in delivering the original hop compounds to
the beer (processing hops alters the volatile hop compounds in many ways).
Disadvantages: They float, so some contact with a still wort (as in dry hopping) is thought to be lost this disadvantage is
certainly arguable though, especially when it is considered that by using weighted hop bags, it is a non-issue. Since they
are loose, exposure to air (oxygen) may be greater which could cause them to lose quality more quickly than the other
forms of hops (note that this point is debatable). When stored in vacuum- sealed or CO2 or nitrogen purged Oxygen
barrier bags or jars, this potential problem can be avoided. They are bulkier than other forms.
Plugs
Advantages: Are nearly the same as loose hops, in that, when hydrated, they become whole hop cones again. Like loose
hops, they float. They may be better protected from air, but this is unproven.
Disadvantages: Few hop varieties come in this form. Currently, any domestic varieties are first shipped to England
where they are made into plugs and then shipped back to the U.S. This probably negates any potential freshness
advantage they have over loose hops (for U.S. varieties). It is difficult, but not impossible to separate into increments
smaller than 0.5 oz. The compression of the hops into this form causes the lupulin glands to burst, which causes a finiteloss of the volatile hop aromatic compounds and could cause increased alpha acid oxidation.
Pellets
Advantages: Convenient to measure and may have better protection from air (another unproven assumption). They sink,
so they get maximum contact in a still wort, as when used for dry hopping (may or may not be an advantage). If they are
subsequently covered with dead yeast, wort contact is mostly lost, so careful timing is recommended when using them
for dry hopping. They reportedly contribute 10% more alpha acids to the wort because of maximized surface area, so are
a more efficient use of this relatively expensive ingredient. They are generally available in more varieties.
Disadvantages: They sink and are powdered, so it is difficult to avoid them when siphoning. The extra processing ofchopping and compressing negatively affects hop compounds.
Given the pros and cons listed, the choice of which form of hop to use in a certain application is up to the individual
brewer and dependent upon the individual brewhouse. With some kettle arrangements (those using a hopback, for
instance) loose hops can form a utilitarian filter bed. In others, the mass of loose hops can be a nuisance and soak up a
large quantity of wort which is lost to the brewer. It should be noted that fresh, whole hops are available today from
many sources, including mail-order nationwide (US) from companies such as Just Hops, Freshops, and HopTech, which
may negate many of the advantages of processed hops.
Estimating Beer Bitterness
The simplest way to describe the bittering potential of a given hop sample is to use Alpha Acid Units (AAU) or
Homebrew Bittering Units (HBU) (they're the same). For the sake of discussion we will use the term AAU, which is
calculated as follows:
AAU = AA * W
where:
AA = alpha acid % provided with the hops
W = weight of the hops in ounces
AAU's are literally hundredths of an ounce, so the units would be ounces. This is a bit awkward, and they are usuallydiscussed as if they are "unit-less". It is generally assumed that, when using AAU or HBU, the batch size is the standard
homebrewing unit of 5 gallons. If a beer is said to have 10 AAU's of bitterness in it, and it is a 5 gallon batch, there
would probably be no confusion. On the other hand, if it is a 10 gallon batch, there is actually half the AAU's per gallon
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when compared to the 5 gallon batch and the beer would be quite different. Another drawback to using AAU's is that
they don't consider the utilization obtained from long, intermediate, or short boil times. Fudge factors are sometimes
added but at best they offer a rough approximation.
To help solve these problems, the International Bittering Unit (IBU) may be used. An IBU is defined as 1 mg/l of iso-
alpha-acid in a solution. By estimating IBUs rather than HBUs, the brewer can get a more accurate (though admittedly
still rough) approximation of the bitterness imparted into the beer by the hops. It is independent of batch size so that a 5
gallon batch with 29 IBU's has the same bitterness as a 50 barrel batch with 29 IBU's. The equations are commonly
quoted from Jackie Rager's article in the "Zymurgy" Hops and Beer Special Edition published in 1990. Revised
numbers and formulae have recently been presented by Glenn Tinseth and Mark Garetz, in separate works. Rager hasbeen taken to task for not supplying enough background references, and not fully explaining how he got his numbers. In
general, his utilization estimates are believed to be optimistic. Garetz has been accused of extrapolating scant laboratory
information, and overgeneralizing because of it. His numbers have been labelled unrealistic on the pessimistic side.
Tinseth has just presented a revised method and set of tables, and though they are thought to be quite accurate, they have
not stood the test of time. The calculated numbers tend to fall in between Rager's and Garetz's. Note also that these are
all estimates. Actual IBUs can be measured in a laboratory, but the average homebrewer has no access to such
equipment. The Rager, Garetz, and Tinseth estimation methods follow.
Rager Method
Boiling Time (minutes) %Utilization-----------------------------------0 - 5 5.06 - 10 6.011 - 15 8.016 - 20 10.121 - 25 12.126 - 30 15.331 - 35 18.836 - 40 22.841 - 45 26.9
This utilization can be reduced to a smooth function, as opposed to the table, which produces many discontinuous lines.
The Rager table is represented by the following utilization equation:
%UTILIZATION = 18.11 + 13.86 * hyptan[(MINUTES - 31.32) / 18.27]
According to Rager, if the gravity of the boil exceeds 1.050, there is a gravity adjustment (GA) to factor in:
GA = (BOIL_GRAVITY - 1.050) ---------------------- 0.2
otherwise,
GA = 0
Metric Units
IBU = (GRAMS OF HOPS) * %UTILIZATION * %ALPHA * 1000 ------------------------------------------------ VOLUME(litres) * (1 + GA)
Non-metric Units
IBU = (OUNCES OF HOPS) * %UTILIZATION * %ALPHA * 7462 ------------------------------------------------- VOLUME(gallons) * (1 + GA)
Jackie Rager's numbers have been used successfully by thousands of homebrewers and provide a consistent base with
which to work. Note that the figures expressed as percent should be entered as decimal values in the formula (9% =
0.09). It is apparent that his constant 7462, derived from metric to US conversion, is actually closer to 7490. The GA
factor could be questioned as well, as it is intuitively obvious that a gravity of 1.049 does not affect utilization exactly the
same as a gravity of 1.000 (water). It is assumed (but not verified) that the utilization table is corrected for this
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assumption and/or the difference is small enough that it has little effect on the final bitterness of the beer.
The unfortunate part of Rager's article is that it is completely lacking in references, so assumptions come with it part and
parcel. Note also that Rager's numbers are often used for pellet hops thrown loose in the boil. Al Korzonas suggests
adding 10% more hops if used in a hop bag, and 10% more than that if loose hops or plugs are used.
Garetz Method
It has been reported that since iso-alpha acids possess a slight electrical charge, they can be lost in many ways. Among
these are absorption into the yeast cell walls (and subsequent removal of the yeast), attachment to coagulating proteins
(and subsequent removal of this trub), attachment to filters, etc. It is unclear if Mr. Rager's utilization numbers have
assumed these losses, but it can be assumed that Tinseth and Garetz did take them into account. The Garetz numbers
below represent average yeast flocculation he also provides tables which represent fast and slow yeast flocculation.
Boiling Time (minutes) %Util (Avg Yeast)----------------------------------------0 - 5 06 - 10 011 - 15 216 - 20 521 - 25 826 - 30 1131 - 35 1436 - 40 1641 - 45 1846 - 50 1951 - 60 2061 - 70 2171 - 80 2281 - 90 23
According to Garetz, there are several adjustment factors, that he brings together in the formula with the term "combined
adjustments" (CA):
CA = GF * HF * TF
where GF is the Gravity Factor, HF is the Hopping Rate Factor, and TF is the Temperature Factor. To calculate it all, he
starts with some he calls CF:
Concentration Factor: CF = Final Volume / Boil Volume,
to account for concentrated boils of extract brews.
Next, calculate Boil Gravity (BG):
BG = (CF * (Starting Gravity - 1)) + 1
Then calculate GF:
BG - 1.050GF = ---------- + 1 .2
HF is calculated as follows:
HF = ((CF * Desired IBUs)/260) + 1
TF is based on elevation as follows:
TF = ((Elevation in feet) / 550) * 0.02) + 1
These are all put into the following formula, along with the utilization from the table, and the IBUs are calculated. Notetwo things: 1) the utilization and alpha acids should be expressed as whole numbers (7% = 7), and 2) this process is
iterative, since it contains a term (HF) based on your goal IBUs. You must guess at the final result, do the math, and
rerun the process, each time adjusting the value downward. It takes a little practice, but can be done.
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Metric Units
IBU = (%Utilization) * (%Alpha) * Hop weight(grams) * 0.1 --------------------------------------------------- Volume(liters) * CA
Non-Metric Units
IBU = (%Utilization) * (%Alpha) * Hop weight(ounces) * 0.749
------------------------------------------------------ Volume(Gallons) * CA
Garetz goes to allow for a yeast factor (YF), pellet factor (PF), bag factor (BF), and filter factor (FF), and comes up with:
CA = GF * HF * TF * PF * BF * FF
This allows you to adjust the formula based on your own brewery and practices.
Tinseth Method
Glenn Tinseth's method doesn't involve as many factors, but is still a bit more complex than the original Rager
method.Tinseth notes that his table is optimized for fresh whole cones loose in the boil, although easily adjustable for
other forms of hops. He builds the gravity adjustment into the utilization tables and offers the following:
Decimal Alpha Acid Utilization vs. Boil Time and Wort Original Gravity
Boil Original GravityTime 1.030 1.040 1.050 1.060 1.070 1.080 1.090 1.100 1.110 1.120 1.130(min) 0 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 3 0.034 0.031 0.029 0.026 0.024 0.022 0.020 0.018 0.017 0.015 0.014 6 0.065 0.059 0.054 0.049 0.045 0.041 0.038 0.035 0.032 0.029 0.026 9 0.092 0.084 0.077 0.070 0.064 0.059 0.054 0.049 0.045 0.041 0.03712 0.116 0.106 0.097 0.088 0.081 0.074 0.068 0.062 0.056 0.052 0.04715 0.137 0.125 0.114 0.105 0.096 0.087 0.080 0.073 0.067 0.061 0.05618 0.156 0.142 0.130 0.119 0.109 0.099 0.091 0.083 0.076 0.069 0.06321 0.173 0.158 0.144 0.132 0.120 0.110 0.101 0.092 0.084 0.077 0.07024 0.187 0.171 0.157 0.143 0.131 0.120 0.109 0.100 0.091 0.083 0.07627 0.201 0.183 0.168 0.153 0.140 0.128 0.117 0.107 0.098 0.089 0.08230 0.212 0.194 0.177 0.162 0.148 0.135 0.124 0.113 0.103 0.094 0.08633 0.223 0.203 0.186 0.170 0.155 0.142 0.130 0.119 0.108 0.099 0.09136 0.232 0.212 0.194 0.177 0.162 0.148 0.135 0.124 0.113 0.103 0.09439 0.240 0.219 0.200 0.183 0.167 0.153 0.140 0.128 0.117 0.107 0.09842 0.247 0.226 0.206 0.189 0.172 0.158 0.144 0.132 0.120 0.110 0.10145 0.253 0.232 0.212 0.194 0.177 0.162 0.148 0.135 0.123 0.113 0.10348 0.259 0.237 0.216 0.198 0.181 0.165 0.151 0.138 0.126 0.115 0.10551 0.264 0.241 0.221 0.202 0.184 0.169 0.154 0.141 0.129 0.118 0.10854 0.269 0.246 0.224 0.205 0.188 0.171 0.157 0.143 0.131 0.120 0.10957 0.273 0.249 0.228 0.208 0.190 0.174 0.159 0.145 0.133 0.121 0.11160 0.276 0.252 0.231 0.211 0.193 0.176 0.161 0.147 0.135 0.123 0.112
70 0.285 0.261 0.238 0.218 0.199 0.182 0.166 0.152 0.139 0.127 0.11680 0.291 0.266 0.243 0.222 0.203 0.186 0.170 0.155 0.142 0.130 0.11990 0.295 0.270 0.247 0.226 0.206 0.188 0.172 0.157 0.144 0.132 0.120120 0.301 0.275 0.252 0.230 0.210 0.192 0.176 0.161 0.147 0.134 0.123
To calculate IBUs, the formula is simple:
IBUs = decimal alpha acid utilization * mg/l of added alpha acids
For those who want to make adjustments based on their own brewery, he offers the following:
Metric Units
mg/l of added alpha acids = decimal AA rating * grams hops * 1000 ------------------------------------- liters of wort
Non-Metric Units
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mg/l of added alpha acids = decimal AA rating * ozs hops * 7490 ------------------------------------- gallons of wort
The decimal alpha acid utilization is calculated using Tinseth's two empirical factors: the Bigness factor and the Boil
Time factor.
Decimal Alpha Acid Utilization = Bigness Factor * Boil Time Factor
The Bigness Factor accounts for reduced utilization due to higher wort gravities.
Bigness factor = 1.65 * 0.000125^(wort gravity - 1)
The Boil Time Factor gives the varying utilization based on boil time:
Boil Time factor = 1 - e^(-0.04 * time in mins) -------------------------- 4.15
Some comments from Tinseth:
"The numbers 1.65 and 0.000125 are empirically derived to fit my data. The number 0.04 controls the shape of the util
vs. time curve. The factor 4.15 controls the max util value--make it smaller if your util is higher than mine.
I'd suggest fiddling with 4.15 if necessary to match your system, only play with the other three if you like to muck
around. I make no guarantees if you do.
You might notice that the shape of the util curves is very similar to that of Randy Mosher's. He and I seem to have
independently arrived at the same conclusion.
The really cool thing about these new equations is that they are easily customizable. I believe the basic form is correct--
by playing with the different factors, different brewers should be able to make them fit their breweries perfectly. The root
of the equations is the basic first order chemical reaction, i.e. the AA isomerization seems be first order (or pseudo-first
order)."
Bitterness Summary
It should be obvious that the alpha acid utilization is a widely debated topic, and that it is not an exact science.
Homebrewing systems vary so widely that it is impossible to be very accurate with the IBU estimates. The homebrewer
who strives to be accurate within 10% of actual can probably achieve it, and verify it with known commercial examples.
The human tongue is accurate enough for this delightful experiment. Precision with IBUs is certainly achievable, with
careful record-keeping, including personal sensory descriptions, and the use of a consistent set of formulae and
utilization tables. These steps will go a long way toward consistent quality beer.
One question that appears on occasion is whether you lose bitterness if you boil the hops for too long, e.g. longer than
two hours. According to Glenn Tinseth, multiple studies have shown that alpha acid utilization always increases withboil time, even out to 3 hours of boiling. The reason the tables quit around 60 minutes of boiling, is that little utilization is
gained beyond that. In fact, after about 45 minutes the curve becomes quite flat. In other words, beyond that the
utilization increase is small compared to the added time involved. It is speculated that commercial brewers found that
beyond 45-60 minutes or so, the benefit of the added utilization was more than offset by the cost of the energy to
continue the boil as well as the cost of the added time in the process.
A final note about bitterness: IBUs are not the final word when it comes to the perceived bitterness of beer. Sulfates,
dark grains, tannins, and other compounds found in beer contribute to the bitterness sensation. For this reason,
comparison of bitterness between styles (and sometimes even different beers within a style) is difficult.
How Bitter Should It Be?The AHA and probably other organizations publish (large) charts which define the range of IBUs expected in a given
style. It is outside the scope of this FAQ to go into that much detail on beer styles, but hopping rates from 10 IBU to 60
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Hop blossoms start out looking like large sand burrs, and then take on a characteristic cone shape as they grow in size.
The size of a fully developed cone depends on the variety, varying from 1 to 2 inches long by 1/2 to 1 inch in diameter.
The hops are fully mature and ready for picking when two changes take place. First, immature hops have a damp, soft
feel and when squeezed slightly tend to stay compressed. Mature hops feel more like paper, spring back when squeezed,
and feel noticeably lighter. The second key test is to pick an average example hop and cut it lengthwise down the center
with a knife. When ready to pick, the yellow powder (the lupulin sacs containing the essential oils and bitter compounds)
will be a dark shade of yellow, like the stripes on a highway, and it will be pungent. If a light shade of yellow then its
likely the hops are immature.
When ready to pick it is best to snip the stems of the cones with scissors or a knife to avoid jarring the hops and
knocking lupulin powder out or worse, pulling the center of the cone out with the stem, causing a great loss of lupulin.
Touching hops plants can cause skin irritation in some people gloves and long sleeves can help in this matter.
Just-picked hops are roughly 80 percent water if left alone they spoil rapidly. For proper storage most of the water is
removed by drying. A good drying method is to lie the hops on a card or screen in an attic. Just a few hours during the
heat of summer or a few hours more in cooler weather is enough to dry the hops. Use a before and after weighing (and
trial and error) to try to achieve about 7-10 percent residual moisture after drying.
After drying, hops keep best at low temperatures and away from oxygen. A kitchen freezer easily takes care of
temperature but to get the hops away from oxygen is difficult. Tightly packing hops in canning jars will minimize the
trapped air but be careful not to use too much force and break the all important lupulin sacs since this accelerates
oxidation. Purging the canning jar of oxygen by blowing in carbon dioxide from a kegging system will also help prolong
freshness.
It's common to get 4 or 5 harvests per year by picking the biggest, most mature hops every 2 weeks or so as the flowers
ripen. Patience and judgement are important since cones left on the vine too long turn brown and begin to oxidize and
spoil, while immature hops have little lupulin to give.
At the end of the growing season when the leaves have fallen or turned brown, cut the vines at the surface of the soil and
if possible remove the twine. After cutting back the vines a layer of 3 or 4 inches of mulch and composted manure can
be put over the exposed vines for insulation and nutrition during the winter.
Japanese beetles are the number one nuisance in many areas. A common remedy is to position a "Bag a Bug" type
beetle trap about 30 feet directly up wind from the hop vines. There is some concern that the "Bag a Bug" traps may
actually attract more beetles than they catch, but that probably depends on the situation. Certain plants such as rose
bushes may also attract the beetles, so it's best to keep those plants away from your hops. Also, the beetles' larvae live in
the ground, and in cases of extreme Japanese Beetle infestation the surrounding lawn may need to be treated
accordingly. A number of other pests, such as aphids, can harm hops, and can be treated with any number of pesticides.
Since you will be consuming these hops, you should use low toxicity natural pesticides, such as 1% Rotenone dust, for
direct pest control on the plants. As with any consumable, you should ensure that any pesticide is well washed before
using the hops.
Ladybugs are the best, most natural way to get rid of aphids and a lot of other bugs. However, it can be difficult to keep
them on your hop plants once you run out of food for them. A good idea is to plant some cilantro/coriander between
your hop hills. Ladybugs are attracted to this plant and it will keep their attention between feedings of aphids. You can
even harvest the cilantro (the leaves) for cooking and use the coriander (the seeds) in Witbier.
One other hazard is animals. A short fence of rabbit wire will keep cats, dogs, rabbits, etc. at bay, but won't do much
against deer.
Rhizomes are available from an increasing number of sources. American Brewmaster in Raleigh, NC, and Freshops in
Philomath, OR, are all well-known suppliers. Cost is usually a few dollars each. They should be kept in plastic bags,
moist and cold in your refrigerator until they are planted.
Additional information about hop growing can be found in "Homegrown Hops" by David R. Beach. Also, the 1990Zymurgy Hops and Beer Special Issue is devoted to hops and contains an article about growing hops by Pierre Rajotte.
The AHA also has additional hops-oriented publications.
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Dry Hopping
Dry hopping can be defined as adding hops to a cooled wort at sometime during the fermentation process. It can be
thought of as "cold-hopping" or "raw-hopping", as these hops do not "cook" like the kettle hops. It adds a fresh hops
aroma/flavor to the beer which cannot be matched with hop additions into hot wort. It is not to be confused with
finish/aroma hopping, which is done on the hot wort while still in the kettle. The use of a hop-back, where hot wort is
passed through the hops, is another form of finish hopping it is not dry hopping. Dry hopping gives no alpha acids to
the wort, but it may contribute some oxidized beta acids its bittering contribution to the final product is very small. It is
more likely to add a perceived bitterness with the addition of the intense aroma rather than an actual bitterness due tobitter acids.
There are several ways to dry hop, if one considers the variations of making hop teas, etc. The best time to dry hop is
after primary fermentation has slowed and little CO2 is being driven off the wort. Dry hopping earlier than this point is
inefficient as the volatile hop oils are scrubbed away by the exiting CO2. Also, dry hopping early in the fermentation
phase may result in hops on the bottom of the fermenter being covered with yeast, which results in inefficient extraction
of aroma. Another consideration of timing dry hopping is with infection risk. Hops in contact with boiling wort are
effectively sanitized. Addition of dry hops after primary fermentation allows them to contact a wort/beer with some
alcohol and less sugar, which prevents infections from getting a foothold.
The proper length of time for dry hopping is dependent on the temperature. At ale temperatures, 7-14 days of contact
time is widely used. At lager temperatures, although little data is available as few lagers are dry hopped, it seems obvious
that longer contact times, on the order of 14-21 days, are called for. It is common to use 0.5 - 2.0 oz. or more in a 5
gallon batch, but as always it is up to the individual's preferences and the hop variety. An ounce or more of East Kent
Goldings in the secondary will add a nice aroma, but probably not overpowering to most brewers. A similar amount of
Cascades, on the other hand, are not for the faint of heart! The rare commercial brewer that dry hops generally leaves the
hops on the beer for a longer time than the average, impatient homebrewer. This is undoubtedly to extract more aroma
from this relatively expensive ingredient.
EKGs, Fuggles, Northern Brewer, Saaz, Cascade, all Hallertauer variants, and many other hops have been used
successfully. It should be noted that the aroma of the beer greatly influences the profile, and that the "correct" aroma hop
should be used to match the style (i.e. English hops for English ales). American brewers have traditionally used hops
from all over the globe so European hops, for example, can be used without fear of a brewing faux pas. Note also thattraditionally, German beers are not dry-hopped, but that American versions of German styles are sometimes dry hopped.
The first and foremost way to dry hop is to simply put the hops into the fermenter. The most common worry with this
method is about infecting a beer which is nearly ready to bottle/keg. Hops are natural preservatives, and infections from
this method are very rare. Of course, an infection source in a homebrewery is impossible to prove, but this risk is
certainly minimal. If loose hops or plugs are used, they will float, and some brewers use a sanitized hop bag and marbles
to sink the hops for maximum contact. If pellets are used they will sink, but may be difficult to avoid when bottling or
kegging. Also, the pellet hops can be easily covered by yeast falling out of suspension, so they should be added after
virtually all fermentation activity has ceased, and a good amount of the yeast has fallen. Finally, it is worth mentioning
that, for many, pellets are not well regarded for dry hopping because the pelletization process is known to be very rough
on the volatile aromatic compounds which the brewer is attempting to capture. Others swear by them, claiming the pre-
burst lupulin glands provide more aroma to the beer.
Another method used to dry hop is to steep the hops in a white alcohol (grain, vodka, etc.) and sometimes water solution
for hours or days, then pour this solution into the fermenter. This is a common practice among those who want to protect
against the remote possibility of infection with normal dry hopping. It should be noted that as the temperature of the
alcohol/water/hops mixture is raised, the effect approaches that of finish hopping, as the most volatile hop oils are driven
off.
Adding hop oil, a product recently introduced to the homebrewing market, is another way of "dry-hopping". It should be
done after primary fermentation has slowed for many of the same reasons.
These dry hopping methods, and others, will produce different results, mainly because the desired compounds are sovolatile. The variety of reactions taking place during processing and fermentation will affect the results. Some have noted
grassy and otherwise unpleasant aromas from the practice of dry hopping, so it is not for all beers, nor for all people. The
"best" method is the one which gives the desired result to the individual homebrewer.
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A final note about dry-hopping: the volatile hop compounds will react quickly with oxygen. For this reason, extra
measures should be taken to avoid mixing with air during bottling or kegging, in order to retain the hop aroma for
extended periods of time. These extra measures may include purging the bottling vessel and keg with CO2, very quiet
siphoning, oxygen scavenging caps, and possibly delayed capping after bottling. This method allows any CO2 coming
out of solution during the bottling process to push the oxygen out of the bottle before the caps are secured. This method
is used by many homebrewers but, as always, the results are inconclusive. The simplest method is to use the oxygen
scavenging caps, which requires no extra effort and little extra cost. For further reference, the Summer 1993 "Zymurgy"
contains an article by Mark Garetz on this subject.
What is a "Hop-back"?
A homebrewer's hop-back is a reservoir connected in-line between the kettle and counter-flow chiller. It is filled with
fresh hops before the flow is started. The hot wort flows through the fresh hops and is quickly chilled by the counter-
flow before entering the fermenter. Many of the volatile hop aroma compounds are extracted and brought into the
fermenter with this process. It is generally thought to produce a flavor/aroma profile somewhere between late kettle
additions and dry-hopping. A good article by Kinney Baughman on building a hop-back is in the "Zymurgy" Gadgets
and Equipment Special Issue, and another, written by Charlie Stackhouse, is in the Fall 1994 "Zymurgy" edition.
Wet vs. Dried Hops?
Yes, you can but at best it is a rough guess as to how much. The rule of thumb is to use 6 times as much (by weight) as
you would dry hops. A safer rule would be to do this and to only use them for finish/dry hopping. Since these hops have
not been tested, the AA% is unknown, and later additions are less sensitive to AA%. It should be noted that some
homebrewers have had mixed results when using fresh hops (poor AA approximation for bittering, sometimes grassy
aroma for finishing).
High Alpha vs. Low Alpha
Will high alpha acid hops contribute the same type of bitterness as low alpha acid hops? The short answer is: probably
not. The longer answer has to do with the oils and resins in the hops. As previously stated, hops bring much more tobeer than bittering. There are different qualities of bittering and many respected brewers agree that a cleaner, smoother
bitter can be attained by using an equal number of IBUs from a low alpha hop. To quote George Fix: "I have always
had a strong preference for low alpha aroma hops, even for early additions for bittering. I find that they give (if fresh!) a
clean and mellow bitter, which contrasts with the crude effects I pick up from high alphas." According to Fix, Narziss et
al cited the ratio of the hop oils alpha-humulene/myrcene as providing a refined flavor, with higher ratios (> 1.5)
providing a positive effect. Fix followed this up with research on the hop resins, and showed that hops with < 30%
cohumulone (as a percent of alpha acids) were preferred. The correlation between the two (oils vs. resins) has not been
shown, but as in all areas where human perception is involved, proof is difficult. The bottom line: bitterness is not all the
same.
Hop Varieties and How to Use ThemDISCLAIMER: Hop substitutes should generally be thought of as "last resort" options. Some of them work better than
others, and of course, the individual brewer must decide which substitutes are best. No attempt was made here to label
"good" and "not-so-good" substitutes, because the opinions vary wildly.
Aroma Hops
The following hops are generally considered aroma hops although in recent years they have started to gain a following
in the homebrew community for bittering as well:
Name: CASCADEGrown: USProfile: strong spicy, floral, citrus (especially grapefruit) aromaTypical use: bittering, finishing, dry hopping for American style alesExample: Sierra Nevada Pale Ale, Anchor Liberty Ale & Old FoghornAA Range: 4.5 - 8%
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Substitute: Centennial
Name: CHALLENGERGrown: UK (Northern Brewerheritage)Profile: spicy aroma, fruity flavorTypical use: dual purpose, aroma and bittering, blends well with other hopsExample: ???AA Range: 6.5 - 8.5%Substitute: ???
Name: CRYSTAL (CFJ-HALLERTAU)
Grown: USProfile: mild, pleasant, slightly spicyTypical use: aroma/finishing/flavoringExample: ???AA Range: 2 - 5%Substitute: Hallertauer Mittelfrueh, Hallertauer Hersbrucker, Mount Hood, Liberty.
Name: EAST KENT GOLDINGSGrown: UKProfile: spicy/floral, earthy, rounded, very mild aroma; spicy (candy-like?) flavorTypical use: bittering, finishing, dry hopping for British alesExample: Samuel Smith's Pale Ale, Fuller's ESB
AA Range: 4.5 - 7%Substitute: BC Goldings, Target
Name: ULTRA (was EXPERIMENTAL 21484)Grown: USProfile: fine aroma hopTypical use: finishing for German style lagersExample: NoneAA Range: 3 - 6%Substitute: Hallertauer Mittelfrueh
Name: FUGGLESGrown: UK, US, and other areasProfile: mild, soft, grassy, floral aromaTypical use: finishing / dry hopping for all ales, dark lagersExample: Samuel Smith's Pale Ale, Old Peculier, Thomas Hardy's AleAA Range: 3.5 - 5.5%Substitute: East Kent Goldings, Willamette
Name: HALLERTAUER HERSBRUCKERGrown: GermanyProfile: pleasant, spicy/mild, noble, earthy aromaTypical use: finishing for German style lagersExample: Wheathook Wheaten AleAA Range: 2.5 - 5%Substitute: Hallertauer Mittelfrueh, Mt. Hood, Liberty, Crystal, NZ Hallertau Aroma
Name: HALLERTAUER MITTELFRUEH
Grown: GermanyProfile: pleasant, spicy, noble, mild herbal aromaTypical use: finishing for German style lagersExample: Sam AdamsBoston Lager, Sam AdamsBoston LightshipAA Range: 3 - 5%Substitute: Hallertauer Hersbrucker, Mt. Hood, Liberty, Crystal, NZ Hallertau Aroma
Name: LIBERTYGrown: USProfile: fine, very mild aromaTypical use: finishing for German style lagersExample: Pete's Wicked LagerAA Range: 2.5 - 5%
Substitute: Hallertauer Mittelfrueh, Hallertauer Hersbrucker, Mt. Hood, Crystal
Name: LUBLINGrown: PolandProfile: Reported to be a substitute for noble varieties, in fact is
http://www.samadams.com/http://www.samadams.com/http://www.realbeer.com/cgi-bin/realbeer/cust_redir.cgi?27273&http://www.merchantduvin.com/pages/5_breweries/samsmith.htmlhttp://www.realbeer.com/cgi-bin/realbeer/cust_redir.cgi?27273&http://www.merchantduvin.com/pages/5_breweries/samsmith.htmlhttp://www.northernbrewer.com/8/11/2019 Calculos de IBU
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said to be Saaz grown in Poland.Typical use: aroma/finishingExample: ???AA Range: 2 - 4%Substitute: Saaz, Hallertauer Mittelfrueh, Hallertauer Hersbrucker, Tettnang, Mount Hood, Liberty, Crystal.
Name: MT. HOODGrown: USProfile: mild, clean aromaTypical use: finishing for German style lagers
Example: Anderson Valley High Rollers Wheat Beer, Portland AleAA Range: 3.5 - 8%Substitute: Hallertauer Mittelfrueh, Hallertauer Hersbrucker, Liberty, Tettnang
Name: NZ HALLERTAU AROMA (an organic version also exists)Grown: New ZealandProfile: Said to be a replica of German Hallertauer MittelfruehTypical use: fine aroma hoppingExample: Coors, Coors LightAA Range: 6 - 8%Substitute: Hallertauer Mittelfrueh, Hallertauer Hersbrucker, Tettnang, Crystal
Name: PROGRESSGrown: UK (Whitbred Goldings heritage)Profile: similar to Fuggles, but slightly sweeterTypical use: bittering and aroma for British alesExample: ???AA Range: 5.0 - 7.5%Substitute: Fuggles
Name: SAAZGrown: CzechoslovakiaProfile: delicate, mild, floral aromaTypical use: finishing for Bohemian style lagersExample: Pilsener UrquellAA Range: 2 - 5%
Substitute: Tettnang (many would claim there is NO substitute)
Name: SPALTGrown: Germany/USProfile: mild, pleasant, slightly spicyTypical use: aroma/finishing/flavoring, some bitteringExample: Common in Dusseldorf AltbiersAA Range: 3 - 6%Substitute: Saaz, Tettnang
Name: STRISSELSPALTGrown: France -- Alsace areaProfile: medium intensity, pleasant, similar to HersbruckerTypical use: aroma/finishingExample: ???
AA Range: 3 - 5%Substitute: Hersbrucker, German Spalt
Name: STYRIAN GOLDINGSGrown: Yugoslavia (seedless Fuggles grown in Yugoslavia), also grown in USProfile: similar to FugglesTypical use: bittering/finishing/dry hopping for a wide variety of beers, popular in Europe, especially UKExample: Ind Coope's Burton Ale, Timothy Taylor's LandlordAA Range: 4.5 - 7Substitute: Fuggles, Willamette
Name: TETTNANG
Grown: Germany, USProfile: fine, spicy aromaTypical use: finishing for German style beersExample: Gulpener Pilsener, Sam AdamsOctoberfest, Anderson Valley ESBAA Range: 3 - 6%Substitute: Saaz, Spalt
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Name: WILLAMETTEGrown: USProfile: mild, spicy, grassy, floral aromaTypical use: finishing and dry hopping for American / British alesExample: Sierra Nevada Porter, Ballard Bitter, Anderson Valley Boont AmberAA Range: 4 - 7%Substitute: Fuggles
Bittering Hops
The following hops are generally considered bittering hops, but some aroma applications have been noted (note that the
examples given may not enlighten the taster as much as the aroma hops in the previous section):
Name: BREWER'S GOLDGrown: UK, USProfile: poor aroma; sharp bittering hopTypical use: bittering for alesExample: Pete's Wicked AleAA Range: 8 - 9%Substitute: Bullion
Name: BULLIONGrown: UK (maybe discontinued), USProfile: poor aroma; sharp bittering and blackcurrant flavor when used in the boilTypical use: bittering hop for British ales, perhaps some finishingExample: ??? (GuinnessExtra Stout and SSWW - not confirmed)AA Range: 8 - 11%Substitute: Brewer's Gold, Pacific Gem
Name: CENTENNIALGrown: USProfile: spicy, floral, citrus aroma; clean bittering hop (Super Cascade?)Typical use: general purpose bittering, aroma, some dry hoppingExample: Sierra Nevada Celebration Ale, Sierra Nevada Bigfoot Ale
AA Range: 9 - 11.5%Substitute: Cascade
Name: CHINOOKGrown: USProfile: heavy spicy aroma; strong versatile bittering hopTypical use: bitteringExample: Sierra Nevada Celebration Ale, Sierra Nevada StoutAA Range: 12 - 14%Substitute: Galena, Eroica, Nugget, Bullion
Name: CLUSTERGrown: US, Australia
Profile: poor, sharp aroma; sharp bittering hopTypical use: general purpose bittering (Aussie version used as finishing hop)Example: WinterhookChristmas AleAA Range: 5.5 - 8.5%Substitute: Galena, Cascade, Eroica
Name: EROICAGrown: USProfile: clean bittering hopTypical use: general purpose bitteringExample: Ballard Bitter, BlackhookPorter, Anderson Valley Boont AmberAA Range: 12 - 14%Substitute: Northern Brewer, Galena
Name: GALENAGrown: USProfile: strong, clean bittering hopTypical use: general purpose bitteringExample: Catamount Porter, Devil's Mountain Railroad Ale
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AA Range: 12 - 14%Substitute: Northern Brewer, Eroica, Cluster
Name: NORTHERN BREWERGrown: UK, US, Germany (called Hallertauer NB), and other areas (growing region affects profile greatly)Profile: fine, fragrant aroma; dry, clean bittering hopTypical use: bittering and finishing for a wide variety of beersExample: Old Peculier(bittering), Anchor Liberty(bittering), Anchor Steam(bittering, flavoring, aroma)
AA Range: 7 - 10%Substitute: Hallertauer Mittelfrueh, Hallertauer Hersbrucker
Name: NUGGETGrown: USProfile: heavy, spicy, herbal aroma; strong bittering hopTypical use: strong bittering, some aroma usesExample: Sierra Nevada Porter & Bigfoot Ale, Anderson Valley ESBAA Range: 12 - 14%Substitute: Chinook
Name: PERLEGrown: Germany, US
Profile: pleasant aroma; slightly spicy, almost minty bittering hopTypical use: general purpose bittering for all lagers except pilsenerExample: Sierra Nevada Pale Ale, Summerfest, and Pale BockAA Range: 7 - 9.5%Substitute: Hallertauer Mittelfrueh, NZ Hallertau Aroma
Name: PRIDE OF RINGWOODGrown: AustraliaProfile: citric aroma; clean bittering hopTypical use: general purpose bitteringExample: Foster's Lager, Victoria Bitter, Coopers Sparkling AleAA Range: 9 - 11%Substitute: ???
Hard to Find Hops
The following hops are relatively rare. In fact, they are rare enough that I haven't found much useful information on
them, but they are included here for completeness.
Name: GREEN BULLETGrown: New ZealandProfile: ???Typical use: Bittering and aroma in lagers, even pilsenersExample: ???AA Range: 8 - 12%
Substitute: Styrian Goldings
Name: NORTHDOWNGrown: IrelandProfile: good flavor and aroma, blends well with other UK typesTypical use: all purpose ale hopExample: GuinnessAA Range: 7.2 - 9%Substitute: Target, Northern Brewer
Name: PACIFIC GEMGrown: New ZealandProfile: delicate black currant/floral noseTypical use: Strong Bittering, but also some aroma applications
Example: ???AA Range: 14%+Substitute: Bullion?
Name: SOUTHERN CROSSGrown: New Zealand
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Profile: ???Typical use: Strong Bittering and fine aroma qualitiesExample: ???AA Range: 11-12%Substitute: ???
Name: STICKLEBRACTGrown: New ZealandProfile: Said to be comparable to European Northern BrewerTypical use: Strong Bittering as well as aroma usesExample: ???
AA Range: 11 - 13%Substitute: Northern Brewer
Name: SUPER ALPHAGrown: New ZealandProfile: ???Typical use: bittering and aroma applicationsExample: Steinlager, Hahn PremiumAA Range: 10 - 13%Substitute: ???
Name: TARGETGrown: UKProfile: accounts for 40% of UK hop production
Typical use: mostly used for bittering, some aroma potentialExample: Young's Special London AleAA Range: 10.5 - 12.5%Substitute: Northdown, Progress
Contributors
Glenn Anderson (gande@slims.attmail.com)
Scott Barrett (adiron!partech.com!scott@uunet.UU.NET)
Jeremy Bergsman (jeremybb@leland.Stanford.EDU)
Jim Busch (busch@daacdev1.stx.com)
Nick Cuccia (Nick_Cuccia@talamasca.berkeley.ca.us)
John DeCarlo (jdecarlo@mitre.org)
David Draper (David.Draper@mq.edu.au)
Alan Edwards (rush@xanadu.llnl.gov)
George Fix (gjfix@utamat.uta.edu)
Bill Flowers (waflowers@qnx.com)
Jeff Frane (gummitch@teleport.com)
Mark Garetz (mgaretz@hoptech.com)
Russ Gelinas (russell.gelinas@unh.edu)
Mark Kellums (kellums1@aol.com)
Al Korzonas (korz@iepubj.att.com)
Rick Larson (rick@adc.com)
Don Leonard (don@tellabs.com)John Palmer (palmer#d#john@ssdgwy.mdc.com)
Bob Regent (b_regent@holonet.net)
Peter Soper (not online?)
Spencer Thomas (spencer.w.thomas@umich.edu)
Glenn Tinseth (gtinseth (at) yahoo (dot) com)
Rich Webb (rbw1271@appenine.ca.boeing.com)
Patrick Weix (weix@netcom.com)
Carl West (eisen@kopf.HQ.Ileaf.COM)
Ed Westemeier (westemeier@delphi.com)
Dave Wiley (wiley@wiley.b11.ingr.com)
Gene Zimmerman (EZIMMERM@UWYO.EDU)
Business catalogs referenced
http://www.realbeer.com/library/authors/palmer-j/http://www.northernbrewer.com/http://www.northernbrewer.com/8/11/2019 Calculos de IBU
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Just Hops--Mount Zion IL
HopTech--Danville, CA
Hopunion USA--Yakima, WA
Further Reading
Kinney Baughman
"Zymurgy" Gadgets and Equipment Special Issue, 1992
David R. Beach
Homegrown Hops
George Fix
"Science in the Service of the Brewer's Art", National Homebrewer's Conference Transcripts, 1994.
Mark Garetz
"Zymurgy" Summer 1993,
"Brewing Techniques" Jan/Feb 1994,Using Hops, The Complete Guide to Hops for the Craft Brewer , 1994
"All About Bittering", National Homebrewer's Conference Transcripts, 1994.
Alfred Haunold & Gail Nickerson
"Brewing Techniques" May/June 1993
Charlie Papazian
The New Complete Joy of Homebrewing
Dave Miller
The Complete Handbook of Homebrewing
Jackie Rager
"Zymurgy" Hops and Beer Special Issue, 1990
Pierre Rajotte
"Zymurgy" Hops and Beer Special Issue, 1990
Quentin B. Smith
"Zymurgy" Hops and Beer Special Issue, 1990
Charlie Stackhouse
"Zymurgy" Fall 1994
Glenn Tinseth
"Brewing Techniques" Jan/Feb 1994
Send feedback to: gtinseth (at) yahoo (dot) com
http://brewingtechniques.com/http://brewingtechniques.com/http://brewingtechniques.com/http://www.belgianbeer.com/http://www.hopunion.com/8/11/2019 Calculos de IBU
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http://www.realbeer.com/hops/http://realbeer.com/Recommended