In an attempt to improve my efficiency I have been looking for recommendations on the best crush settings. Homebrew forums generally state a range of 0.026”-0.038” from what I’ve seen. ProBrewer forums, and master brewer podcast, both state a course crush to provide a better efficiency by keeping husks intact to act as filter. I’ve seen many on ProBrewer forums state 1.5-1.7mm is best. That comes out to 0.059”-0.067”. I use feeler gauges to set gap. Anyone have experience with adjusting gap settings and how it impacts their efficiency?
Like so many things in the brewing world, it's probably going to be system dependent. You might get a great crush, but maybe your brewhouse is where the efficiency lacks, for example. Or maybe the mill your using is a different kind of mill from Joe's down the street and results in different crushes even though the rollers are set the same distance apart. The only true way to dial your whole system in is to experiment and record data. Overtime, you'll get an idea as to what a good crush would be for you and how you need to run your system get the best efficiency. That being said, it helps to get some input as to where to start. You may already know this, but breweries that utilize agars intentionally set their mill to be more coarse, as the grain will be crushed even more as it travels to the mash tun. The measurements you saw on pro brewer might have been wider due to this factor. I'm not sure if you're willing to spend the money or not, but to get the best reading of the courseness/finess of your gain, you can conduct a sieve test. Page 20 on this pdf talks about how to conduct this test and the tools you need for it. This will give you an idea as to how good your crush is. Here is another link that talks about good percentages for homebrewers to use. Try starting here, brew a batch, record your efficiency, and if you don't like it, start again.
My first thought is I wonder if those recommendations are based on 3 roller mills, rather than 2 roller mills that most homebrewers use. Also, I think you're more likely to find smooth or slotted (vice knurled) in a pro setup than in a homebrew setup. And then there's motor speed, and probably some other things I'm not thinking about. ETA: and then there's roller diameter.
Another source of error is using the feeler gauge, it's not like a numerical setting is a single point. With the feeler gauge inserted do the rollers move easily or does it take a lot of force or ? ? ? Pretty sure two people could use the same gauge and with a different technique end up with a significant difference. FWIW, I set my rollers at 0.030 somewhere between a tight-loose grip on the gauge. Agree that keeping good notes is as important (more?) as the setting.
I set mine at 0.038". I constantly get 75% efficiency. I dont recirculate mash or anything. Just chills in my mash tun. We did start at 0.030", and half the time we would have a stuck mash or a stuck sparge. What I ended up doing, was a lot of research, got a set of feeler gauges, then I bought 5lb of 2 row and adjusted the mill until I got a crush were all the kernels were open, but the husks were mostly intact. Get a set of feeler gauges (Amazon, doesnt need to be expensive), and trial and error it out.
.035 for most. Had to use .025 for the naked oats and spelt. I use feelers but you really need to look at it.
I set my mill at 0.039" and I consistently achieve 75% efficiency. I periodically (every 6 uses or so) check the gap with a feeler gauge. Cheers!
I'm at 0.032"...that size works well for my system and I get 85% efficiency. I feel bad for anybody that doesn't achieve a minimum of 80% efficiency (shaking my head condescendingly...)
I crush at about 0.32. No sparge getting usually around 70% efficiency on anything less than 6.5% ABV. Anything over 7% and I’m getting about 60% efficiency
What do you feel are the benefits of no-sparge, low-efficiency mashing? And related to this, what gap do you use on your mill? Cheers!
Well, the lower efficiency just comes with the territory, but with no-sparge I believe I get richer, cleaner malt flavors than with batch or (especially) fly. I also don't need to worry about tannin extraction during the sparge. I should probably add that when I no-sparge, I'm not using all the water in the first infusion. I typically mash-in at about 1.5 qts/pound, then mash-out with the remaining water. Beats me. I haven't measured it in a long time and don't have a clue where my feeler gauge set is. When I (rarely) adjust it, I do it by examining the crush.
