Recipie Confusion

[2FistedChugQueen]

Me and a friend are sitting down to make our first batch ever, and we've been going through some recipes....

When the recipes start talking about hops, it says things like (5% AA, 60 min.). What does this mean?

 

[Chairman Cheyco]

Allow me.

www.howtobrew.com

Welcome to the Board!

 

[david_42]

AA = alpha acid This is the main measure of bittering ability. A 15% AA will make a brew 3 times as bitter as a 5% AA. So, one oz. of 10% Nugget will bitter a brew as well as 2 oz. of 5% Fuggle, if they are boiled the same amount of time.

 

[the_bird]

The minutes refers to the number of minutes the hops are boiled for. Most beers are boiled for 60 minutes, so you add bittering hops ("60 min") at the beginning. Flavor and aroma hops are added later in the process, with the minutes representing the total time they should be boiled for, i.e. hops additions labeled "20 min" are added after 40 minutes and boiled for the last 20.

 

[2FistedChugQueen]

OK, thanks for the link, info, and the welcome. Cheers!

 

[disaffected]

Some recipes might specify hop additions in ounces, like .75 ounce Cascade. Some recipes list the hop additions in AAU's (alpah acid units), like 5 AAUs Northern Brewer. I should think it would be uncommon to specify hops by percent Alpha Acids. That is a designation of the acid content of a particular species and crop by weight. The hops from each crop are analyzed to determine the percent Alpha Acids by weight.

AAU (Alpha Acid Units) = HBU (Homebrew Bitterness Units) = %AA times X ounces of hops

So solving for X, you calculate the weight of hops you need as
X = AAU / AA%

If a recipe calls for 6 AAU's of Cascade hops and Cascade has a AA% of 6.4, then
X = 6 / 6.4
X = .9375 ounces

So why do some recipes specify the hops as a certain number of ounces of a particular variety, while others specify them in AAU's? I am not sure, but I have a theory.

The recipes that specify hops by weight and variety are assuming that a particular weight of a certain hop contributes sufficiently close to the same amount of bitterness all the time. As long as the AA% analysis of a particular hop species varies little from crop to crop, this is a reasonable idea. Small differences in AA% from year to year make little difference to the homebrewer. If you are a large commercial brewer who must maintain strict controls to ensure that you achieve the same taste batch after batch, then you wouldn't make that assumption.

Recipes that specify hops in AAUs have a couple of advantages. The brewer who is trying to achieve consistency (e.g., the commercial brewer, or the small brew pub, or the anal-retentive home brewer) can vary the weight of the hops to account for AA% variations from crop to crop. Also, if a brewer wants to substitute a different hop for the one called for in the recipe, he can calculate the weight of the substitute that would provide an equivalent amount of bitterness to the brew if he knows the number of AAUs he needs and the AA% of the hops he is using..

That's my theory, anyway.

And, welcome to the forum.

 

[Beer Snob]

Me and a friend are sitting down to make our first batch ever, and we've been going through some recipes....

When the recipes start talking about hops, it says things like (5% AA, 60 min.). What does this mean?

Means you take hops rated at 5% AA and boil them for 60 minutes.

 

[Dude]

AA = alpha acid This is the main measure of bittering ability. A 15% AA will make a brew 3 times as bitter as a 5% AA. So, one oz. of 10% Nugget will bitter a brew as well as 2 oz. of 5% Fuggle, if they are boiled the same amount of time.

That's a good explanation.

I made a thread about this a while back, with the formula from BYO:

https://www.homebrewtalk.com/showthread.php?t=2887

 

[2FistedChugQueen]

We cooked up the batch last night and it's now sitting over in the corner fermenting....

Thanks for everyone's help!

 

[david_42]

If you get a cheap mechanical kitchen timer, it counts down the minutes for you. Just crank it to 60, toss in the bittering hops & then wait for the next addition to roll around.

 

[Denny's Evil Concoctions]

Just a note. when you seem 60 min 15 min etc. It the time before falme out. In other words boil for the last 60, last 15 etc. It doesn't mean steep them ingrain bag for the first 15 the remove as I remember some one once telling me that it what they did.