Affects on beer when mash temp drops from 152 > 140's

My last two beers have been on the thin/watery side despite hitting the OG and FG. For reference they are Cream of Three Crops and Bee Cave Haus Pale Ale.

In my process, the thing I've honed in on is my control (or lack of) of mash temps. After I hit my target mash temp of ~152, I stir and maintain for a few minutes. Then come back in say, 10 or 15 minutes. Since I have an uninsulated kettle the temp may drop to ~148. So I fire up the burner and heat up while stirring.

Is this enough to affect general body and mouthfeel since the upper 140's make thinner beers? Since conversion could happen within the first 15 minutes or half hour could the dropping temps be enough to not lock in a style you would get at 152 degrees (versus lower).

I'm working on moving to electric, so at some point I'll be able to set my PID to 152 and keep the pump running the whole mash. Until then its manually turning on and off my propane burner.

Kevin

I have a separate mash tun with no burner. Throw a big comforter over it and the temp maybe drops 4 F over a 90 minute mash.

In answer to your query though your beers should finish lower gravity, be drier, and have a little less body. Although with heat under the mash tun all bets on that may be off.

What do you mean by that last part of bets off with heat under that mash tun?

It means if you mash without heating at 148 (or lower if it keeps dropping) then you will have very fermentable wort and therefore thin, higher ABV beer. Too low temp by the way might affect efficiency FYI.

IF you start heating the tun, then all bets are off and depending on what temp u heat to, you get a less fermentable, lower ABV wort.

My advice is get a cheap cooler and convert for better insulation. I lose 0 degrees over 60 min mash in my cooler wrapped in a wool blanket.
Or get that electric system up and running. It would drive me crazy to chase my tail during the mash and heating and cooling.

And to address the OP, yes it would affect the overall mouthfeel and other characteristics of the beer.
Consistent temps are key for the mash IMO.

Or just insulate the tun you have with Reflectix type insulation...maybe $20 will make a HUGE difference. Also, If you drop 4 degrees in 10-15 minutes I suspect the mash was already lower than you thought from the start and just not stirred enough.

At a minimum use a much thinner mash so your total thermal mass is higher and will therefore drop in temp more slowly.

I actually have a roll of that. Just don't want my kettle to look gheto. But if applied with care should look nice.

I had the opposite problem a while ago. Kept getting nice full body beers with a higher FG though. Turned out my dial type thermometer was about 5 degrees too high. :smack:

Thanks for the feedback everyone.

kevreh said:

I actually have a roll of that. Just don't want my kettle to look gheto. But if applied with care should look nice.

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Let me guess, you live in a gated community? Afraid of what the neighbors will think?

I cannot imagine sacrificing consistency for aesthetics...but I drive a beater by choice and think Target is high fashion.

Onkel_Udo said:

Let me guess, you live in a gated community? Afraid of what the neighbors will think?

I cannot imagine sacrificing consistency for aesthetics...but I drive a beater by choice and think Target is high fashion.

Click to expand...

Ha ha, no not really. Point taken. Just hesistant with a shiney new kettle and all. But the improved heat retention will make up for it.

kevreh said:

What do you mean by that last part of bets off with heat under that mash tun?

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Just that if you are allowing it to cool, then reheating it, you may get different results than just allowing it to cool. The part of the mash that is closest to the burner is getting way hotter than you might think, if you are heating up the whole batch back from 140 to 152 for instance. So you may not get a much thinner body because at least some of the mash may have already been "mashed out". Other than a decoction mash, why mess with heating it back up? Ghetto it with your insulation!!!

Check your thermometer before every session (boiling water) to make sure it is reading correctly. I couldn't figure out why my brews kept finishing with really low FG's till I discovered my thermometer was reading 6 degrees low at mash temps.

I switched from biab to batch sparge in a cooler because I got tired of chasing mash temps. My brew days are more relaxed and my beers more consistent. Insulation on a mash tun is a good thing.

As suggested by others, check your thermometer. I recently dumped a batch because my thermometer started reading 8 degrees wrong. I mashed at 145 instead of 153. Made for a very thin and astringent beer.

I bought a digital *calibrated* thermometer for fairly cheap - I think it was less than 20 dollars. Even came with a calibration certificate. This is a MUST if you are an all-grain brewer.

Also, keep in mind that most of the conversion takes place in the first 15 minutes or so, and happens faster the higher your temps are. At 152 initially, you probably got a decent conversion before the drop. It will have a lighter mouth feel and a lower FG, but no big deal. If I was uninsulated I would just turn the burner on low periodically and stir the mash for a little bit. You'll figure out a routine that works. Best to just insulate it, though - and add boiling water periodically as needed, and stir it in.