I know that most people start to see a drop in efficiency when going above 1.060. I am planning a 3.5 gallon batch that should have an OG of 1.077 or so. Does batch size influence the change in efficiency? I would assume not.
Any estimates on how much of an efficiency drop I should expect? I was thinking 5 points but wasn’t sure if that would even be enough.
I don’t see any efficiency drop until I get well over 1.080.
+1… Me either
Okay thanks. 1.060 stuck in my head for some reason. I guess I will just estimate using my normal efficiency and see what happens.
I would do your calculations like you would do normally. If you fall a few points shy, you’ll know that you’ll need to make an adjustment next time. I give my recipes an opportunity of error of +- .003. Your potential extract from grain can vary. I also figure that I’m mashing in a cooler, boiling in a keg and fermenting in a plastic jug… It’s not a perfect process every time. 
Very true. Sometimes I try to be over prepared for a first batch and then up disappointed because my results differ from my expectations/calculations. I am starting to get better at using a first try as more of test batch from which to develop
It is great that you put the effort into being perfect. Trust me, I want mine to be spot on too… Actually… I brewed yesterday and after a rocky start of running out of propane while heating my mash water and brain farting on my strike temp by 10 degrees, which lead to a lot of stirring… I nailed my target OG.
I did my first barleywine a couple weeks ago and target OG was 1.100. My normal efficiency is 73ish %… I rolled the dice with this at 60% efficiency calculated and hit a gravity of 1.104… I was jumping up and down that I was close!
+2
I get a little better efficiency with smaller batches because then you can sparge more as the boiloff rate far exceeds the typical 15-18%. With 2-gallon batches my boiloff rate is like 32%, so by sparging a lot more to get your appropriate pre-boil volume, you can extract extra sugars.
Not the batch size per se, but like Dave says, if the boil off rate stays constant your efficiency will increase for the smaller batch.
Are you batch sparging? Batch Sparging Calculator « SeanTerrill.com
My efficiency was lower than normal. OG ended up at 1.070 instead of the predicted 1.078. I followed my normal process. Predicted 8.3% ABV beer will be lucky to get above 7.5%. Bummer…but at least it is basically a test batch…
I must have jinxed myself by thinking my efficiency would drop to being with. It was almost exactly 5 points lower which I predicted in my original post…haha