Some info I thought I?d share with you folks ? I?ve tried overnight mashing a few times with good results. One down side is I prefer to brew in the evening vs. the morning. On Thursday I started the mash prior to leaving for work in the morning. The mash started at 7:30AM @ 156F. I did my first runnings at 5:45 PM . The temp had dropped to 144F. I had my mash cooler inside a sleeping bad and covered with a down coat. I had a HUGE efficiency improvement of 17% (I batch sparge so it usually sucks at 60%).

In addition I was done brewing and cleaning up by 8:30 PM . With times like this I could be brewing on weekdays if necessary ? some time its hard to schedule a brew session on the weekend.

Tim

I've heard of people using this method with good success. Been tempted to try it myself. If you take an eight hour brew day and break it up into segments it can be more accommodating. I may have to use this method since I cannot devote most of a day to brewing and still produce the quantities that I want. I don't want to have to work on various days I have off.

Supposedly it has no effect on efficiency; however, I feel that one's observations over time have validity in their own brewery and may not apply to another's. I take it you are no-sparging and not batch-sparging? You shouldn't get such poor efficiency with batch-sparging unless your crush is not fine enough. I think that is pretty universal.

Anyway, thanks for reminding me that I can do this too!

Why would the efficiency be any better?

I've seen an increase in efficiency by mashing longer.

Surely there's an explanation for the increase? It's easy for me to say I caught more fish one day then another because I used a different fly but the reality is there are a lot more factors at play. I'll have to do a split mash one day, I need another IPA anyway.

The only thing I think it could be that the little nuggets of (endosperm?) have additional time to break down thereby releasing just that much more sugar into the solution.

I don't know guys....I oh-so look forward to that day of brewing, 8hrs of me and the dog with the house to ourselves....I think I might brew this week

Me 2 Brewboy...

i've seen an increase, too.

Hmmmm...I'm one of those who hasn't seen an increase in efficiency due to a longer mash. I don't buy that it gives the enzymes more time for conversion. Using almost any malt these days, you'll get conversion in 20-30 min. A long mash will affect your FG however. I wonder it someone is defying the laws of chemistry, or of there's another explanation.

I too have seen an increase. Maybe if you r crush isn't really fine, then the extended time allows more starch to dissolve into the wort. If you have a finer cursh and more flour, maybe you don't see a change. At least this is an easy hypothesis to test. Right now I crush with a barley crusher set at the default gap(I think 0.039". Cursh is probably just right for fly sparging, crushed, but the husks are still intact without uncrushed husks. I think for batch sparging I could tighten it donw a bit and see if that gives me the same efficiency as mashing overnight. Right now I get about 74% for a standard 1 hour mash and more like 81 for an overnight mash.

the only explanation i can come up with has to do with physical access to the starches, not time for conversion. if, during a shorter mash, all the starches don't have a chance to go into solution (of, if they're in large chunks, the enzymes can't access the inner reaches), that could be remedied by a longer soak. and perhaps the reason it doesn't improve all brewers' efficiencies is that we've all got different crushes. if you're already getting a fine crush and good efficiency, then you aren't likely to see much of an increase. but if, like me, you're dealing with the LHBS's somewhat coarse grind, you stand to benefit from giving those larger chunks more time to hydrate and convert. not unlike the bump brewers see when jumping from an inefficient fly-sparge system to batch sparging. it levels the playing field, but won't necessarily give you a leg up if you've already got your parameters in order.

just a theory, but one i think could account for some brewers seeing an increase and others not.

I think there's as much chance of that as that it's attributable to something else that's being overlooked.

i won't deny that. still, in the absence of that something else, i think it's a plausible theory. only a controlled test -- by the same brewer -- could say for sure.

"only a controlled test -- by the same brewer -- could say for sure." using the same bag of malt, the same recipe, the same water, the same crush.....

exactly. or, to test my theory, using two different crushes for a total of four batches: one short and one long with the finer crush, one short and one long with the coarser crush.

so... any volunteers?

Since mashing in is a pretty quick procedure, I often start it over the lunch hour and finish the brewday after work, giving me a 4-5 hour mash . . .

"only a controlled test -- by the same brewer -- could say for sure." using the same bag of malt, the same recipe, the same water, the same crush.....

I was planning this experiment for a brew in the next week or two, I'll just split my grains in half and do two mashes for the same batch and see what happens. I would start both mashes at the same time and just lauter and sparge the "normal" mash right away and then wait for the long mash to get but then then I'd be using a cylindrical cooler and a rectangular cooler and I'm sure there would be different results.