How much Hops?

[sweetwater]

In a typical 5 Gal batch I see a variety of hops and amounts, 1oz to 5oz called for in similar recipes(Ales, etc). What determines the amount of Hops, when to add, etc etc. If dry hopping is so good, why do we add to the boil at all?
I'm brewing a batch of Ale this weekend and the recipe calls for 1oz of Kent goldings @60 min., is that enough?

[b3s]

what determines the amount of hops is the bitterness rating and the recipe creators palate.

AAUs are fairly easy to calculate. one ounce of kent goldings per hour is somewhere between 4-6 AAUs. This is derived at in the following manner:

AAU = quantity of hops x AU rating as hole number

AU rating is a percentage. for kent golding it's usually in the 4-6% range, although the ones i got today are above 7%.

therefore: AAU(60) = 1 x 7 = 7.

to calculate IBUs is a bit more tricky.

take the AAU rating above (number of ounces times AU rating of hops as whole number) and multiply by 75 and again by number of minutes in boil. then divide this number by the gravity of the boil.

given 1 oz. KG for 60 minutes, i know for me that's a bit light. i prefer around 10-14 AAUs for 60 minute hops and another 5-10 for 15 minutes...then whatever trips my trigger at the time for aroma. YMMV.

one thing to do...go to www.hbd.org/recipator and use their online spreadsheet for your recipe.

[Stodbrew]

Dry hopping only adds flavor and aroma, not bitterness. The purpose of boiling hops is to isomerize, or solublize, the alpha acids in order to impart bitterness.

[Beerconnoisseur]

Originally posted by sweetwater
In a typical 5 Gal batch I see a variety of hops and amounts, 1oz to 5oz called for in similar recipes(Ales, etc). What determines the amount of Hops, when to add, etc etc. If dry hopping is so good, why do we add to the boil at all?
I'm brewing a batch of Ale this weekend and the recipe calls for 1oz of Kent goldings @60 min., is that enough?

There have been many great points made above, so I will add the following:

Different hop varities are used for different styles of beer. For example, many of the Amercian Northwest hops (Amarillo, Cascade, Galena, Yakima Magnum, etc.) will add more of a grapefruit/citrusy taste to your beer. Contrast this with the noble hops (the different Hallertauer, Saaz, Spalt, and Tettnanger), and you will get more of a Continental European flavor. Others, like English hops (Bramling Cross, East Kent Goldings, Fuggles, and Williamette[an American version]) will give an earthy flavor which some prefer.

Hops added for 60 minutes or more will contribute mostly to the bitterness of beer; you may see references on this board to Dogfish's 120 minute India Pale Ale. If the hops are added with 2 to 5 minutes left in the boil, then they will be most noticeable in terms of flavor. Hops added with a minute left in the boil are typically noticeable for their aroma contribution.

Depending on the amount of grain/extract you are using in your recipe, only adding 1 oz. of Kent Goldings for bittering will make a beer that accents the malt character more. One way to add hop complexity to a beer is to mix several varities of hops, but keep the total quantities low. You could add 0.5 oz. Fuggles and 0.5 oz. Kent Goldings at the aroma addition, and decide for yourself if it's good....

[brewmonkey]

To figure IBU's

IBU's= (weight in oz * AA%% * 7489)/(Vol in USG * Gravity)

To calculate what you need in oz for a given addition

(Deisred IBU's)(Vol USG)
Woz= --------------------------------
(AA%)(U%)(7489)

[b3s]

oh, right, i forgot volume...damn.

otoh, i don't go by IBU, i go by AAU(time) and figure from there. when my boils are bigger than 5 gallon i'll figure out the appropriate ratio...i rely on software to figure IBU.

i stand by my original assertion...i prefer a 10-14 AAU boil and a 5-10 AAU aroma and that it winds up being a matter of palate preference.

the variety of hop is also useful as the type imparts a flavor (less important at 60, more important at 15 or less, imo). for instance, you won't find too many of my beers with tettnanger (again) just cuz i don't like the flavor.