So i just bought a whole bunch of hops from the LHBS, and all but two variates where a higher A.A than my online recipe calculator, nothing like having to re-adjust your recipe after your purchase, my IPA was raised about 14IBU’s before i redid the addition times and my ESB was raised about 19IBU (also due to the fact the my intended variety (Glacier (5ish A.A) was mixed with Galena (11.4 A.A)), but still glad i was able to rerun the numbers before i brew tomorrow. I know that the A.A% changes from year to year and even harvest to harvest, but these differences could really affect a beer if your not careful.
Anybody else have experience with this?
I’m not sure what you mean by experience . . . you always have to check the alpha acids on your hops and adjust your recipes. That’s just a fact of brewing.
You’re lucky though, imagine if the AA% was lower than what you had in your recipes, you’d need to go buy more. 
When you go to the store with your recipe, include both the weights and AA% for the hops. Then you can adjust as needed at the store.
Well i was talking with one the guys on the LBHS and he mentioned that he has heard many stories of people not double checking the numbers and having beers that were either way under-hopped or over-hopped and “not drinkable”.
So i guess that is what i was trying to say, if anybody has forgotten to double check and “ruined” a beer?
The hops that are on hand go into the recipe on my computer program and quantities are adjusted up or down to hit the target. As Tom said it is a fact of brewing. You can find hops from different growers or fields from the same growing year that will have different AA values.
Then there is always the question of how well the AA number from the sample taken matches the AA of the hop you actually bought? Or how much have those hops degraded from the testing for AA to when you use those? I try not to overthink it.
Whenever I get new hops I put it into my Beersmith inventory at the %AA listed on the package. That way I know what I have when I’m planning out recipes.
That’s one of the few mistakes I have not made, but I’m sure it’s happened plenty. It’s definitely one of the things you double check when building your recipe once you get in a routine.
Dave
I have a book of recipes which lists hop types by name and has addition type (bittering, flavor, aroma). It doesn’t include AA% or addition time so it is pretty useless…
^^^ This ^^^
does include IBU numbers? that’s a place to start at least. If you know the IBUs you can play aroudn with different schedules and amounts to hit that number.
Or really you should be able to plug it in to a calculator and change the AA% until the IBUs match what’s in the book. Then go from there.
I can’t say I recall making the mistake of not checking my hops, although I’ve made beer with hops of unknown AA%.
I generally keep the original packaging the hops came in that shows the AA%, and write the purchase date on it. That way in ProMash I can enter the starting % of AAs in each new recipe, and if they’ve been stored for awhile calculate the loss-over-time factor. I vacuum seal any opened hops, but left inside the original packaging inside the vacuum sealed bag, kept in the freezer of course. I really like using a vacuum sealer and keep plenty of felt tip markers on hand, and it’s easy enough to read the original packaging labels through the vacuum sealer bags.
Any experience with hops of unknown AA% AND unknown variety? Got an ounce as swag from a comp.
Use them as a flameout addition for an APA maybe?
Hmmm, I do have an APA that’s just about ready for dry hops. Don’t know if I have the guts to try the “unknowns” though.
Give 'em to somebody. Throw 'em away. It’s only an oz.
With an ounce there’s not much you can do. Smell them, if you like the smell use them late or for dry hopping. Or as Denny said, toss them, that’s fine too.
My only experience with unknown hops as when we brewed at an old hop farm and picked the hops that were growing wild on the telephone poles in the area. The smelled ok going in. The guys who were in charge of the fermentation didn’t like it so they tossed it without letting anyone else taste it. We still give them grief over that.