Originally Posted by kontreren
Anyone explain the alpha values in simple english? For example recipe X calls for 1 oz. Gallena hops (5.5 alpha) but I use 1 oz. Gallena (10.8 alpha). What is that going to do to my beer? I don't really understand the whole alpha thing.
Geeze, in simple English? That could be hard, how about simple math?!
Another way to look at hops is as units of acid... Alpha Acid Units or AAU's might make it easier to understand.
Let's first put aside the fact that certain hops are better for bittering, and other hops are better for aroma.. and also some are good for both bittering and aroma... but let's put that aside for a minute.
Ok, AAU's so an AAU for a hop is the alpha acid of that hop so in your example 1 oz of Gallena at 5.5 alpha is 5.5 AAU's If you have some Gallena 10.8 Alpha it would be 10.8 AAU's ... to find out how much 10.8 Gallena you would need if the recipe called for 5.5 AAU's you would just divide the original AAU's by the AAU's in what you have on hand... so in this case
5.5 / 10.8 = .51 and since we are talking about one ounce here that means to get the same result you would use .51 oz of the 10.8 hops...
So, the 10.8 hops is just about 2x as strong so you use 1/2 as much to get the same result.
What will doubling the amount of AAU's do to your beer? Well, beer is a balance between sweet malt and bitter hops. The more hops you put in the more bitter and less malty the beer becomes. It is however hard to say exactly what that means to a nonexistent beer. The influence of the hops is dependant upon the gravity, the base malts, the mash temp, and other factors. So it is hard to say what effect doubling the AAU's would have w/out knowing anything more about the beer. To some beers it would make them very hoppy and to others it might not be as noticeable.
Hope this helps?