Mashing for longer...

[hommebru]

Had a thought the other day about people who mash overnight and the problem being that the temperature drops too much and they end up with a wort that's more fermentable and ends up producing a thin beer.

This idea is based on mashing at your usual of 65-66 degrees and then it drops to 60 or below, but what if you were to start the mash at 69-70 and then let it mash till it dropped to 65 instead?

would this improve efficiency and not compromise the fermentability of the wort?

Like I said, it's just an idea which i haven't researched or anything like that so if i'm barking up the wrong tree just let me know.

[boingy]

I've mashed across a working day plenty of times and not really noticed the thin beer thing even though the temperature drop is significant.

It seems to me that it's the temperature during the first part of the mash that matters most. As long as the first hour or so is at my target temperature then it really doesn't seem to make much difference whether I leave it 1 hour or 10 hours. I have not done any particular study of this so this is just my observations. No doubt the geeky technical bods will be along shortly to tell you how you will burn in hell if you do an overnight mash.

There is one definite disadvantage to long mash times. The wort is cooler so it takes longer to get it up to the boil.

BTW, I think you'll need a pretty good mash tun to only drop 5 degrees overnight!

[critch]

youd end up with an barely fermentable beer full of tannins



yuk.

[seymour]

I agree with boingy and critch. It's the temperature during the first 60-90 minutes that determines which enzymes do all the heavy-lifting of converting starch to fermentable sugars. If you strike too hot at the beginning, you kill all the enzymes, thus barely converting any starches, and instead just stewing-out lots of rough-tasting tannins (think astringent nuts and shells, seeds, fruit pits, squeezing a used tea-bag, etc).

This is mostly semantics since most homebrewers use the same vessel as a mash tun and lauter tun, but perhaps it would help you to think of creating normal mash conditions, then doing an extremely long sparge. Does that make sense? Super-long sparges are fine for us, to get the most sugars for our money, or simply because of timing/convenience concerns (as boing stated.) Commercial breweries have the opposite pressure: "time is money" so they're willing to trade-off absolute highest possible mash efficiency in support of moving as much beer through their system in as little time as feasible, thus increasing sales revenue, reducing wages, etc... Watery beer clearly isn't the reason they don't do a slow sparge.

If you have the time and want to do a really slow sparge, go for it, but resign yourself that it might be slightly thinner and have slightly more tannins, no matter what.

[hommebru]

thanks guys, it all makes sense now you've applied some logic and science to it all.
i guess it would be more efficient to do a longer sparge and then keep going until you hit 1.008.
i surprised that it's been alright for you though boingy, i thought the purpose of the mashout was to stop enzyme activity and to preserve your wort's sugar balance, so to carry on mashing must make some sort of impact?

[boingy]

I daresay it does have an impact but perhaps not a very significant one. Some commercial guys will sparge for hours on end, gradually approaching a mashout temperature but not for ages.

I think there are a few folk doing long or overnight mashes and I assume they are happy with the results. Some of my beers are better than others but I've never really had a problem with excessively thin beer. I guess you should try it for yourself. One overnight, one not. Same recipe, same yeast, same fermenting conditions and see if you get a lower FG with the overnighter. If the FGs are within a point or two of each other you will probably be hard pushed to taste the difference, depending upon the beer style.

I haven't done a long mash for a little while but my next one may well be, due to forthcoming commitments.