dlgoff said:
Okay. I just returned home with a couple of gallons of my favorite Wheat State Golden. I realize that it must be hard to make consistent batches as I taste slight differences every time I get a refill. But today has the best hops flavor yet. So my question is, "What is the secret of consistency?"; from your experiences.
Things that affect the hop profile is the amount of hops used, the alpha acid content, hop boil time, the gravity of the wort during the boil.
If it is the same brew being made, more then likely the wort gravity will be the same, or close enough, from batch to batch. Also the hop boil time would likely remain the same.
That really leaves the amount of hops and the alpha acid content as variables.
The alpha acid content is usually shown as a percentage, i.e. 5.75% AA. The value varies from type of hops and from season to season even within a single type of hops. Each type does have a "known" range of the %AA, i.e. cascade hops may be 4-7%, but I've gotten some at 7.5%.
For homebrewers, there is a simple formula; weight of hops in ounces x %AA = Homebrewers Bittering Units. W x %AA = HBU
so if one batch you used 2 oz of cascade that had 6.5% AA, you had 13 HBU. If you are then later wanting to make the same, but this time your cascade has 7.5%, algebra shows you only needs about 1.75 oz. The exact amount is 1.7333, but I would weigh out 1.75oz.
For professional brewers, the math gets a bit more complicated, especially as the amount of hops needed to achieve the same perceived bitterness increases as the gravity during the boil increases.
If the perceived bitterness varies from batch to batch, its probably due to a bit more hops being used or the hops had a bit more %AA. Even how fresh the hops were at the time of brewing will affect it as well. Picking them straight from the vine into the pot is about as fresh as you can get. The longer they are stored, the lower the %AA will drop over time.
If buying hops for homebrewing, if the place does not have the %AA and does not store them in at least a refrigerator, or a freezer, do not buy them there.