AA Levels

Hello Everyone,

I have a question concerning Alpha Acid levels in hops. I’ll be making Jamil’s Cali Common recipe from Brewing Classic Styles in a couple of weeks and as I was putting the recipe together in BeerSmith to make adjustments for my system, I noticed that the AA levels in the Northern Brewer hops in recipe were 6.5%, and then noticed that the hops I purchased were labeled as 10.6%. This cut the amount of hops I need by roughly a third (Glad I checked! My beer would have come in at 62 IBUs instead of 42), but I was wondering if it is common for these percentages to vary so widely. I always thought that the percentages were generally within one or two points across the board for a given hop variety - apparently this is not so?

So many variables in growing hops (any food item) that things can vary by a large percentage.

The AA should be the same in one harvest year. As the growers will blend the crops from different fields and areas of the field.

From this year to next, or from last year, yes there could be that much of a difference.

The acid content will vary from year to year, crop to crop. Beersmith has a default percentage assigned to all its hops but you may have to adjust it to match your hops. The northern brewer hops I got last year were around 8.5.

Nighthawk you must have replied while I was still typing +1

I learned to watch out for this when mine were actually significantly lower than listed in beersmith. Beer wasn’t bad, but could definitely used more of a bittering addition.

Hops usually vary by a few percent, Northern Brewer hops are listed in the NB catalog as being in the 8-10% range. You definitely want to check that, although honestly you’re looking at a test that was done on some bales of hops and so theres variation as well as storage conditions that could make what you are brewing with somewhat different. I don’t count on it being all that exact.

Thanks to all - I guess I have a new line item on my recipe-building checklist.