Overnight Mash

[Bribie G]

Just did my first overnight mash for ages, doughed in at about 10 PM at 68 degrees and finally got back to it this morning at 10.30 when it had dropped to just under 60.

I was interested in whether I would get better efficiency. I'm not an efficiency tragic, but a few extra points could have skewed the hop additions a bit out of whack as it's a Yorkshire Bitter Special/Best/Premium bitter for a comp and I didn't want to knock it up into the Extra Special/Strong category, as it's borderline as it is.

Pleasingly it came out absolutely bang on my OG of 1045 as predicted by BrewMate with my usual 75% eff.

I'll be doing a few more overnighters, I find it's easier to tackle cleanup in the morning as opposed to later at night after a few jugs

 

[RdeVjun]

Agree for sure WRT the late- night clean up Bribie, one of the reasons I prefer an earlier start, can't really be arsed too much after tea time!

 

[Jack of all biers]

I wonder about whether you're likely to get more tannins leaching out over a longer period. Just a question, really, no basis for it other than soak anything long enough and osmosis happens.

I supposed if you control alkilinity it would reduce that effect.

See http://braukaiser.com/wiki/index.php/How_pH_affects_brewing for a possible answer, although the length of time spoken about on this thread is not discussed. I would think more tannins would be released into the wort due to the simple factor of time allowing more into the wort, but not because of osmosis and probably not too much that it would be too noticeable in the flavour of the end product.

I need a bit of clarification here; does one need to hit beta amylase mark, and let it do its thing before hitting alpha amylase territory for a successful stepped mash, or will it work as effectively in the reverse? I always stick to a mid-range of the two with a mash temp of 66 degrees, but could I do a reverse stepped infusion in that I start high and bring the temp down over some time, as Bribie has done, with the same end-result as a traditional stepped mash?

Yes and No. Or as the Germans say Jein. If you want to step mash then you would need to start in the lower beta territory of 60-64C and step up to the alpha territory of 67-72C. Reversing the temp steps is problematic as beta tends to denature (no longer work) at temps 67C or higher. So if you started your mash at 68C and left it for 10 hours, by the time it got down to 62C (optimal temp for beta) they would already have mostly denatured from being at the high temps for so long. Striking a happy medium and mash at 65-66C to allow both beta & alpha to do their thing at the same time, as you have been doing, is probably a better option if you can hold your temp in your mash tun for that period.
See http://howtobrew.com/book/section-3/how-the-mash-works/the-starch-conversion-saccharification-rest for the simple answer or here for a more technical in depth look at enzymes. https://www.ibd.org.uk/learning/learning-resources/technical-and-training-material/94/technical-training-material/?pageID=2 (thanks again to MHB for the second link)