if you read old threads and articles about making low alcohol/no alcohol beers one of the techniques is to actually boil or near boil the beer post fermentation, as this drives off alcohol.
I suspect your friend is applying bad math and hoping it all goes to plan.
…Sharks with frickin laser beams…
Perhaps he was talking about the double mash that Randy Mosher described in his last book. That is where you collect the runnings from one mash, then use that as the mash water for a second mash (with new grain).
Speaking of high gravity efficiency, on my last batch of Belgian Strong Dark I was shooting for 85% (which I have been getting consistently) and a 1.090 OG. However, on this batch I got an OG of 1.106 which would equate to a 95% efficiency. I did not believe it but I calibrated my refractometer and my hydrometer matched it. I don’t think I mis-weighed the grain either. Collected volume was good too. I did have a 4 lb sugar addition but I accounted for that in the recipe. Perhaps Pro-Mash is not calculating the sugar gravity points correctly.
The point is to let more sugars dissolve out of the grain into the water. May not seem like it would help, but it really does.
A few minutes of stirring should get any remaining sugars dissolved into the sparge water. If you’re getting an efficiency boost by doing that extra 30 minute rest, you probably didn’t have complete conversion in your initial mash rest.
But that’s contrary to the theory of batch sparging. And why wouldn’t it be generally applicable to everyone? Why don’t I or others see efficiency oncreases from it? I think you have another issue.
I think that there is additional conversion happening. Next time you do this you may want to record these numbers:
grist weight
mash water volume
gravity of well mixed wort that you ran off first. You can test that in the mash tun if you have a refractometer. When using a hydrometer make sure you cool the wort in a closed vessel to eliminate evaporation.
water volume added after run-off
gravity right after stirring in that water
gravity 30 min later.
Based on this we should be able to reconstruct what’s happening.
Kai
Beats me why you don’t see efficiency increase. I can get up to 90% that way with a low grain brew like a bitter, while the regular way gives me ~65-70. 75-80% with bigger grain bills. Don’t think it’s conversion because I did a 2 hour mash once and it ran off at around 65%, while 60+30 min gives me considerably higher yield. Seems pretty logical to me…
Well, if it works for you it works, but I think you’re misattributing the reason.
Isn’t it more or less common knowledge that a mash out can accelerate conversion? I know that when I incorporate one I can count on >95% conversion, whereas after a 60 min rest I’ve occasionally seen CE as low as ~85%.
Yeah, although I wouldn’t call it a mash out if the purpose isn’t to denature enzymes. I’ve found that raising the grain bed temp at the end of the mash does increase my efficiency. But I don’t do any kind of rest with it. Just stir in the water, vorlauf and run off.
Good point. I shoot for ~72°C, then recirculate for 15 min. I guess it’s just an alpha-amylase rest at that point.
It seems that many brewers still think the mash out boosts efficiency by making the wort less vicious add opposed to speeding up conversion. But Sean is correct, the conversion is boosted.
You can easily be at only 85% CE even with a 60 min mash. Especially with a coarse crush. I have seen this in my brewing.
Kai
I see 60-65% eff all the time in my brewing and that’s why I ask the homebrew store to crush my grains twice (they’re nice enough to do it since we’re all living in apartments here and almost none can afford such luxury as to have grain crushers or store sacks of grain at home) after which it goes up to 90 sometimes, but generally hangs around 75-80 for mid-grav brews. I’d love to get an even finer crush, but there is only so much that can be done in these conditions. Perhaps I misspoke… It generally takes me about 30 minutes to get the first runnings to the stove and do the rest of the mumbo-jumbo before I get to collect second runnings, so that’s why my magical number is 30 minutes. Indeed I cannot see any possible boots in conversion with a mashout+second water since it denatures the enzymes, but I think it does boost up the solubilization and results in my observations. Anyway, I’m not saying “convert or die”, just stating my observation and what works for me because it seems to be somewhat tangent to the topic of this thread.