Humor me, hold my hand (and tell me I'm pretty) [hops calculation]

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woozy

woozy

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Tell me if I have the concept right. (Although in practicality I suppose it won't make much difference.)

I'm using a 5-gallon batch recipe to make a 2-gallon batch of Cream Ale. The recipe calls for 1 oz. of Cluster hops at 8.0% Alpha Acid. My store doesn't carry Cluster so I got Northern Brewer at 9.5%.

So in *theory* I figure 1 oz. at 8.0% = x oz. at 9.5 percent. Solve for x to get x = 8.5/9.5 = 17/19. Multiply x by 2/5 to get .36 oz but I can figure that's close to 3/8 oz (.375).​

Of course, I could *also* figure: The 1 oz to 5 gallons were probably determined for convenient measuring. This hop is roughly 1/8 stronger, I'll use roughly 1/8 less if it's convenient for measuring. Otherwise they are close enough. 2/5 of 1 oz is .4 oz but it's convenient on my scale to round that to 3/8 (.375) oz... and that's a bit less so it'll do.

But am I correct in the concept? You adjust your amount for the acid percentage? Right?
 
All I'm saying is that when it comes to minor things like acid % or rounding to the nearest 1/4 oz, I always err on the side of too much hops. It takes a lot of extra hops to make a beer come out more bitter than you wanted; it seems like it only takes falling a bit short to make it too sweet.
 
woozy said:
Tell me if I have the concept right. (Although in practicality I suppose it won't make much difference.)

I'm using a 5-gallon batch recipe to make a 2-gallon batch of Cream Ale. The recipe calls for 1 oz. of Cluster hops at 8.0% Alpha Acid. My store doesn't carry Cluster so I got Northern Brewer at 9.5%.

So in *theory* I figure 1 oz. at 8.0% = x oz. at 9.5 percent. Solve for x to get x = 8.5/9.5 = 17/19. Multiply x by 2/5 to get .36 oz but I can figure that's close to 3/8 oz (.375).​

Of course, I could *also* figure: The 1 oz to 5 gallons were probably determined for convenient measuring. This hop is roughly 1/8 stronger, I'll use roughly 1/8 less if it's convenient for measuring. Otherwise they are close enough. 2/5 of 1 oz is .4 oz but it's convenient on my scale to round that to 3/8 (.375) oz... and that's a bit less so it'll do.

But am I correct in the concept? You adjust your amount for the acid percentage? Right?
Click to expand...
hold on. let me check with beersmith to see if it's right ;)
 
BetterSense said:
All I'm saying is that when it comes to minor things like acid % or rounding to the nearest 1/4 oz, I always err on the side of too much hops. It takes a lot of extra hops to make a beer come out more bitter than you wanted; it seems like it only takes falling a bit short to make it too sweet.
Click to expand...

So if your recipe called for 1 oz 8% and you had 9.5% you'd do an oz, but if you had 7% you'd do an oz and a quarter? And if you were scaling to 2 gallons you'd do 1/2 oz in general? (.4 * 8% = 32. vs. .5 * 9.5 = 47.5; not worth worrying about?)

Fair enough.

For a home-brewer, I probably like hoppiness less on average than my fellow home brewers but I would hate to have a beer too sweet.

(Heh. My scale does do grams. It's the damnedest thing. In imperial its (digital) display is to the nearest eighth of an ounce but in metric it's accurate to a single gram. But there is such a thing as obsessing when me, myself, can't tell a damned difference. I figure I should just do imperial and reckon all to the nearest 1/8 oz. But that's a different story.)
 
To reiterate what Malfet said above - adjust for bittering, like you did (correctly). However, for flavor and aroma additions, AA% doesn't much matter. Instead keep the ounces/gallon the same regardless of AA%. If your flavor and aroma hops are much different in terms of AA% from the recipe, you may need/want to adjust your bittering addition to compensate for the IBU difference. Also, I generally find it easier to measure hops in grams - better precision, especially on my kitchen scale.
 
Thanks.

Yes, I am talking bittering.

And I *could* measure in grams.

(1 oz = 28.35 grams @ 8% = 2.268;
x grams @ 9.5% = 2.268;
x = 23.87 = 24 grams;
2/5 * x = 9.54 = 10 grams = .3527 oz = 3/8 oz.)

But then what would I write in my notes and recipe? Well, probably just that.
 
If your flavor and aroma hops are much different in terms of AA% from the recipe, you may need/want to adjust your bittering addition to compensate for the IBU difference.​

I don't have the slightest idea how to do this.

But as this recipe doesn't have *any* aroma and flavoring it isn't an issue.

But suppose, for sake of my learning, My recipe called for 1/2 oz bittering 1/4 oz flavor and 1/4 aroma all at 8% but I substituted entirely with 16%. So let me speculate....

The original recipe is 1 oz at 8% for 8. I want to keep my flavor and aroma and 1/2 oz @ 16% that's also 8. So..... I don't use any bittering at all?

Or if I substituted all three with 12% then that'd be 1/2 @ 12% = 6. I need 2 more. Hence I'd use 1/6 oz @ 12% = 2 for the bittering?

Do I have it???
 
woozy said:
If your flavor and aroma hops are much different in terms of AA% from the recipe, you may need/want to adjust your bittering addition to compensate for the IBU difference.

I don't have the slightest idea how to do this.

But as this recipe doesn't have *any* aroma and flavoring it isn't an issue.

But suppose, for sake of my learning, My recipe called for 1/2 oz bittering 1/4 oz flavor and 1/4 aroma all at 8% but I substituted entirely with 16%. So let me speculate....

The original recipe is 1 oz at 8% for 8. I want to keep my flavor and aroma and 1/2 oz @ 16% that's also 8. So..... I don't use any bittering at all?

Or if I substituted all three with 12% then that'd be 1/2 @ 12% = 6. I need 2 more. Hence I'd use 1/6 oz @ 12% = 2 for the bittering?

Do I have it???
Click to expand...

You're on the right track, but it's more complicated than that. IBUs are both alpha acid AND boil-time dependent. The less you boil a hop, the less bitterness it gives you. You'll have to do some research on how hop utilization changes with boiling time, or use some software. It is not linear.

When I change up the hops for a given recipe, I'll figure out the IBU contribution from the flavor and aroma additions first and then add enough bittering hops to hit my target total IBUs.
 
Maths make my brain hurt.

All work and no play makes Homer something-something.... go crazy? Don't mind if I do!
 
aiptasia said:
All work and no play makes Homer something-something.... go crazy? Don't mind if I do!
Click to expand...

Wasn't the quote all work and no beer...?

Heh, heh. Irrelevant to everything remember when Marge became a cop and arrested Homer and said "You have the right to remain silent" and Homer says "I chose to waive that right. BLEAGH! YAARHH!! HROOO ...."

That always makes me chuckle.
 

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