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9

Alpha acids are compounds found in the flower of the hop plant and are the primary source of bitterness in beer. The alpha acids are isomerized in the boil to form iso-alpha acids. The degree of isomerization and the level of bitterness extracted is determined by the length of time the hops are boiled. The alpha acid rating is the amount of alpha acid by ...


8

This is a nice technical question involving some organic chemistry I do not comprehend. I'll begin with what I do know about bittering contributions from alpha acid and beta acids. These acids are components of the hop cone and contribute to bitterness in slightly different ways. The more familiar one is probably alpha acid since most hop bags are labeled ...


4

Your best bet is to use them for flavor and aroma, since then you can use them as is. If you wanted to use them for bittering you'd have to find some way of measuring the bittering acids, such as boiling in a light sugar solution for 30 mins, doing the same with another known AA variety and comparing/diluting until you can get some idea of the bitterness. ...


3

Yes, hops contain two major organic acids generally refereed to as alpha acids and beta acids. When hops are added to boiling wort about 40% of the alpha acids undergo a thermal isomerization to form isoalpha acids. Iso-alpha acids are the actual bitter compound found in beer. When people talk about IBU they are talking about the concentration of isoalpha ...


2

Short answer, "yes". Long answer ... Excuse me for getting a little sciency, but ... Using the simple assumption the "flavor" is a single component with concentration X(t) with a some half-life g, and that the "bitterness" comes from the isomerization of a single kind of alpha acid, with concentration Y(t) and some half-life h, one can write down simple ...


2

Efficiency* will be lower (due to alpha acid degradation) and aromas will be missing, and you'll likely have some cheesy/sweaty off-flavors from isovaleric acid. Toss them and buy some fresher ones. *edit: changed from "utilization".


2

Between myself and my co-brewer Scott and his father we have a total of nine plants, of mostly different varieties. We get a nice crop of hops out of it. But to be honest, not enough to bother having them analyzed. In a dried state, we get a few of ounces of dried hop flowers per plant, enough for a few beers each. Coupled with the fact we are growing ...


1

The AA content of hops is seasonal, and depends a lot on the weather. What you see listed in books is "typical", but that doesn't mean it can't be higher or lower than that. You should always adjust any recipe to the AA of the hops you;re using. Don't match weights of hops, match IBU contributions.


1

Since you are already substituting cascade hops instead of centennial hops, you are not going to hit some pre-destined goal. So you might as well go with personal preference. If, when you drink an APA or IPA, you don't like a lingering bitter, then cut back proportionally on the bittering addition (usually the 60 minute addition). If you like the hop ...


1

You could try juniper berries or possibly spruce. The wiki article mentions several herbs that were used in making gruit. http://en.wikipedia.org/wiki/Gruit


1

Alpha acids are what cause the bitterness during your wort boil. The higher the %, the more bitter they will cause your beer to be during boiling.


1

I've been considering growing hops myself (in Madison, WI) and depending on how successful I am with that, I'd potentially be interested in having an analysis done.


1

The easiest way to figure hop substitutions is the use the Homebrew Bittering Units calculation. simply multiply the hops AA by the amount called for. For example, 1 oz. of 8% AA hops equals .5 oz. of 16% AA hops. There's no need to involve utilization at all.


1

I like the IBU calculator in Beersmith. Available at www.beersmith.com. the trail version will let you use it for 14 days, and the whole program is only $19.99. It lets you change hop types and times and automatically calculates your IBUS based on those choices. It also calculates for boil size.


1

This is a tough one to get right as there are a few formulas for calculating IBU's. This site includes a description of the two main ones and an online calculator you can use to get the numbers you need. Note that none of the formulas are perfect and will give different IBU readings. It's important to choose one and adjust to taste from there. Regarding ...



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