Hi everybody - Doubt hits me and I seek confirmation please. I am scaling up a brew and the hops needed can't be found with the same AA. I understand that - for the bittering hop I tweak the quantity to get the same IBU but for the aroma hops - do I just get the proportionate quantity or do I need to match the AA too? Thanks Matt
Here's what I normally do: - Keep the flavor aroma hop quantities the same. - Adjust the bittering hops so that the total recipe IBUs come out the same as the original recipe (which compensates for the lower AAs in the flavor/aroma hops also). IMO flavor/aroma compounds do not have a 1:1 correlation with Alpha Acids. IIRC, I think the "For the Love of Hops" book suggests otherwise, but in my experience, I disagree with that, at least with noble and english hops, which I tend to use more than other hops.
I agree with @VikeMan -- 1) Keep flavor and aroma hop amounts proportional, then 2) Adjust bittering amount to match IBUs within + or - 3 IBUs (very few people can detect a difference of 2-3 IBUs).
How and what are you scaling up are you scaling up? I would have a different answer if, say, you were scaling a standard ipa up to a dipa or triple.
it is scaling up an old 5 GAL pale ale to a 10 Gal. I had brewed it a few years ago. So same recipe but more volume. Thanks
You have the same variety but the AA% on the package is different, correct? No sweat. Go ahead and scale appropriately. Remember that hops are an agricultural product and there is always some variation. In other words, don't swear by what the bag says. AA% will change in time anyway, so even if the package was 100% accurate at harvest and packaging it is probably not accurate today. Depending on the variety it can change a lot (talking to you Cascade). The big pro brewers go to great lengths to minimize variation, and the pro small brewers might pull their hair out trying to do the same or just accept it and move on. Doubling the size is probably as great an influence as some minor AA% changes anyway. Boil off rate, hop utilization all the way to how the yeast do their job is going to influence the beer as much if not more than a few AA% points. In other words, the double batch is going to be at least moderately different than the original 5 gallon recipe. Not unless you have a very serious home brewery and a ton of expertise can you nail these 2 brews the first time around. Or maybe even the 5th or 10th. Cheers.
Scaling up volume may effect the finished brew for many of the above mentioned reason. I'd say adjust for bittering, yeast pitch and you will be closeish.
Yup, the AA% will decrease with time and there is a formula out there to guesstimate this loss. Here is a link to a calculator which is based on that formula: http://www.brewerslair.com/index.php?p=brewhouse&d=calculators&id=cal16&u=eng Have you see anything similar for the loss of essential oils? Cheers!
I would take any calculators like this with a grain of salt. GIGO. We know that hops are a whole lot more than just the AA%. We know that some varieties keep better than others. What we don't know so well, yet, is how all of the different minor compounds degrade, interact with each other and otherwise make the hop a hop. Using more hops to compensate for a predicted loss of AA is also going mean you change, possibly by a lot, the ratios of the numerous chemicals in the plant. For example, if I don't know, Farnese is very stable and you increase your AA% by 50%, you are also screwing up the balance of Farnese. It might not matter all that much of course. So I personally think, add more and don't expect perfection. Cheers.
