overnight mashing - any issues with fly sparge temps?

[Kev888]

I'm considering mashing overnight, and know that a few people have tried this with success. But I'm wondering if there are any problems then raising to the right temperature during fly-sparge (given that the mash will have lost more heat beforehand)?

I recently moved up to 10kg grain bills and am only just about getting the grain bed up to temperature by the end of the sparge; my intention is to double that to 20Kg for session beers so not quite sure how that'd work out if it all started off much cooler than I'm used to.

Cheers
Kev

[floydmeddler]

I've mashed for around 10 hours. Think temp was in the 50s when I returned. I fly sparged at 80c. No problems.

I found this helpful:

http://www.brewboard.com/index.php?showtopic=30815

[Kev888]

Thanks - thats really useful. It seems my concern is perhaps justified then.

Hmm, I've not got room for a true batch sparge if I get to full capacity brews but maybe there's a hybrid approach that I could use, or maybe I could fly sparge more quickly initially to get up to temperature.

Possibly its not as bad as I fear though - larger volumes will indeed take more effort to re-heat for the sparge, but should also lose temperature more slowly during the night.

Thanks once again,
Kev

[floydmeddler]

I'm assuming you're referring to this section:

The other drawback is that you'll need to pay extra close attention to holding temperatures as steady as possible. I experimented with many coolers and setups before I settled upon one that held the temperature to my satisfaction. In a 6-hour mash, I typically lose only about 8 or 9 degrees F. If you lose too much, it can affect your efficiency (especially if you don't do a mash-out) because the sparge water won't get the grain bed hot enough to liquefy the sugars properly.

Drain off the wort quickly into boiler, heat it up to around 90c, add back into MT, give it a good stir, recirculate for 20 mins then fly sparge at 80c? That's all I can think of and that would take as long as a mash so stupid idea!

No seriously... My efficiency was bang on 80% with this particular brew. 80% is my usual so no change there. If you're worried, my advice is to mash at around 75c. That way it may well still be in the 60s when you come back to it. In terms of worrying about a high FG due to a high mash temp, S04 (in my experience and 3 of my friends' experience time and time again) will still ferment down to around 1010. This yeast doesn't seem to respond to the high temp mash = high FG theory. I've mashed at 65c and 75c and both beers (same grain bill) stopped at 1010.

My advice is to give it a try. You'll never know otherwise. I personally reckon you'll be OK.

[Kev888]

Hi, yes thats it, combined with the batch sparge sentence that follows it:
"I find that overnight mashing works best in combination with batch sparging".

I won't have space to batch sparge full capacity mashes but I'll probably do as you say and just give it a go at some point, I guess the ony way to find out is to try it. I already prepare the ingredients and water the night before and have the HLT on timer, which saves me a useful few hrs on brew day, mashing over night would save another hour and a half (ish) so it would be useful but fairly easy to negate if more work is needed after the mash, and maybe not worth the saving if I have to compromise on mash temperatures and so on.

I'm still refining what I know of the various temperature characteristics of my latest setup at the mo, and haven't yet risked a full 20Kg+ mash which I'm sure will be different again - its really then that brew day time savings will be most useful. Maybe I'll get it fully nailed with conventional mash times to start with, and then have a go overnight to see how it compares.

Thanks once more,
Kev

[dcq1974]

I have to agree as I've recently switched to overnight mashing (in a cool box) with batch sparging and have had no problems in carity or taste/aroma of finished brew.
The biggest downside is that my normal house ale increased from 4% ABV to well over 5%!!!!!!
I need to check this for a few brews to be sure however.

[Kev888]

Hmm, interesting. seems slightly catch22 in a way - I would mainly benefit from overnight mashes when doing full capacity volumes, and thats exactly when I run out of headroom in the MT for batch sparging. Oh joy

Cheers,
Kev

[floydmeddler]

May be of interest to you Kev.

I brewed yesterday and ended up mashing for over 5 hours. Mashed pretty low anyway so wasn't surprised to discover that the middle of the grain bed was around 54c. I treated 3L of water, brought it to 100c and fly sparged it through. Middle of grain bed climbed to around 70c. Continued with my 85c sparge water after that. Efficiency - 80% just like always.

Was slightly worried about tannins being released but as soon as the 100c water hit the grains it immediately cooled so shouldn't be an issue.

[Kev888]

Yes, spot on: its the tanins that were putting me off really; hotter sparge water is easy but I was concerned about the effects. It clearly works for you but I'm a bit dubious about it with my MT - having shelled out on a large stainless tank I'm finding it takes 'a lot' of warming in addition to the grain bed and so I've already been tempted into using hotter sparges (takes a long tame to warm it up and then overshoots by the end) - I can detect a bitter after-taste on the ones I've done this with. However once warmed up it is excellent at maintaining heat through the mash and now I've worked out what sparge temperatures work its very consistant there too, but its not so good at the temperatures being changed.

Beginning to think that maybe my setup just isn't ideal for this sort of thing; I didn't plan for it so I suppose it shouldn't be a surprise. On ballance perhaps it'll just be better to get up an hour earlier and keep everything consistant...

Cheers
Kev