[quote=“dobe12”]Ok, I see two easy solutions.
Use buckets to ferment. They’re like 6.5 or 7 gals and will have plenty of head space even if you ferment 5.5 gallons of beer in them.
When building your recipe, bump up your estimated efficiency for your lower gravity session beers. For example: I generally hit 75% eff (plus or minus 3%). So that’s the estimated efficiency I use when building my recipe. If I started hitting 85% and my sessions were getting up to average strength beers, I’d just start using 85% for my estimated efficiency when building a recipe. That way you’re using less grain but your recipe should still be in line.
If you already have recipes built and just want to adjust them, then re-enter them into whatever program you use and set your efficiency to what you’ve been getting. You should see your estimated OG go up to what you’ve been getting. Then just start backing the grain down until you get back to the OG that you were hoping to hit.
Not to poke fun, but for a chemist I would think a solution to this problem would come easily. And too be honest, your problem isn’t a problem at all. It’s an issue that any brewer would love to have. If your issue was your gravities were too low, then you’d have a completely different set of things to look at in your brewing process. Your current issue is that your brewing process is TOO good for lack of a better term. Smile, it’s a good problem [/quote]
I agree especially with #2. If you have the ability to go back through the batches you’ve done and look at efficiency and OG, you should get a handle on what happens on your system as your OG goes up or down. If you can’t, start keeping track.
Why change to brew-in-a-bag if you get good & consistent results with the techniques you’ve been using? In my mind, you’d just be starting all over again to understand how to hit the OG consistently.
If I’m not mistaken, efficiency only affects the yield from the malts that require mashing. So if you are adjusting the grain bill, just do it with your base malts and keep the speciality grains unchanged.