How to maintain the mash temperature?

Post #1 made 7 years ago
Hi all! Very much a newbie here. I just completed my second all grain BIAB and had a difficult time keeping the mash temperature anywhere near the desired 153F/67C. Any pointers, or just do not worry?

- electric range
- 4 gallons in a 30L pot.
- wrapped with towels when it was off the heat
- It dropped 10 degrees over 30 minutes.

I put it back on the heat, it started to overshoot, I had to use the wort chiller to bring it down, undershot, added heat, repeat... The flippin' thing won't cool down when I want, but just try to maintain the mash temp and it drops like a stone.
I should have thought of that.

Post #2 made 7 years ago
Get yourself an old duvet or sleeping bag. even a couple of fleecy coats. Prewarm your lagging in the tumble drier or over a radiator before use. Towels are not ideal as they are not particularly good at trapping air which is the thing that stops the heat loss.
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Post #3 made 7 years ago
I personally use sleeping bags in sub freezing weather,and the hold the temp well enough that I only have to add heat a few times in a 90 minute mash.
Is there any reason you can't just put your kettle into the prewarmed range below?
I have also heard of guys using old electric blankets as well.

Post #4 made 7 years ago
Will your pot fit in your oven? Some guys set the oven as low a temp as it will go and then stick the pot inside to prevent temp loss.

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Post #5 made 7 years ago
Thank you for the ideas. I will try them out with plain water before the next brew day. It seems I must learn the equipment, like how fast it loses heat, how long to put the burner on, and the effects of residual heat from the electric range top.

First I will try heavier insulation. Fortunately I know how to use a sewing machine to custom fit a duvet or quilted jacket. An electric heating pad... hmm ...

The oven might work although my back is already protesting the idea of lifting and moving 20kg of 150F fluid and grain. The lowest temperature setting is 170F. It is a bit high but it could cool for a minute or two and then have the insulated pot in there. The smaller temperature differential will help reduce heat transfer.
I should have thought of that.

Post #7 made 7 years ago
I use an STC 10000 to control a herms unit. The wort recirculates through the herms and stays exactly at the set temp...thats in winter.

In summer i use good old camping mats and towels. It drops a degree or so over 60 minutes, but thats fine... its means there is less to have to clean up at the end of the day :thumbs:

Post #8 made 7 years ago
I have a duvet cover stuffed with polyester ceiling insulation that I wrap around my pot and a pillow case filled with the stuff to place on top. I only lose around 2 deg F over the course of the mash and I'm sure that happens when I take the lid off to give it a stir.

Post #9 made 7 years ago
Lacking a Herms unit but owning a sewing machine, I cut up an old comforter or duvet and sewed a sweater and cap for my 30l pot. 1 1/2 wraps around, and a pad for the top. Must add Velcro to hold it better.

I thought I hit the mash temp of 154F and put on the lid and cap. It soared beyond 160F. A-ha, residual heat from the range electric element. Moved it off the hot element and left the lid off until things stabilized. Much fussing, and then I got it - trust the strike temp and stop worrying.

Efficiency was miserable - had to add DME to get near the desired OG. But it smells wonderful. Local grain, local malt hose (the grain was still warm from the roaster), local hops, and I'm going to try priming with local maple syrup. We will see.
I should have thought of that.

Post #10 made 7 years ago
you may find that the actual temp is not dropping, :think:

most large amounts of grain and water will hold a good temp,
i thought mine had dropped 8 deg when mashing..?

but it was the grain insulating the thermometer as when i stired the mash the temp went back up,
so it may be the measuring rather than heat loss, :salute:

Post #11 made 6 years ago
I use a roll of silver insulation material available at Home Depot by the roll. Cut to size and wrap the kettle and fit a piece over the lid. I do smallish batches and only lose 5 degrees over 90 mins. I brew inside on the stove and don't like the idea of flammables on/around the stove.

Post #12 made 6 years ago
Tagging on to what thughes recommended, I also use the oven method with great sucess. I pull out all the racks, set the temp to 170F. Once the covered kettle goes in the oven I turn off the oven and let it sit. I do not stir the mash nor do I check temps. I mash for 90 min and only drop one degree, and I'm getting over 80% efficiency into the kettle. Good luck!

Post #13 made 6 years ago
I use Foam insulation but am losing a degree every 10 mins, the temp goes up and down (as I reheat to try and maintain temp) like a heart monitor. The beers taste ok (great) but I would like to try and improve. I might follow some of the advice above and move over to a duvet /sleeping bag.
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Re: How to maintain the mash temperature?

Post #15 made 3 years ago
sanatic12 - yes, just about anything works for insulation.

I use an old duvet wrapped around a 30L kettle on a gas camp stove about 3 feet above the ground. When wrapped, the bottom is still open to the air, but I lose only one or two degrees C over 45 minutes - then I unwrap to stir. If I wish to heat again, I remove the duvet before lighting the burner. After the burner is off, re-wrap and then it is fine through the next 45 min. of mash.
Last edited by ShorePoints on 22 May 2017, 00:05, edited 1 time in total.

Re: How to maintain the mash temperature?

Post #16 made 3 years ago
I did my first biab the other week, and I was very happy with my mash temp. stability.
I have a old cupboard I lined with foam and made new door out of ply and foam.
This my fermentation chamber, add ice to keep fermentation temps down. yeah. like a cooler box/ esksy.

While I was raising my mash water to strike temp. I had another pot boiling away.
After grains added and stirred ,added both to my fermentation chamber. The boiling water pot kept the temp up.
I didn't drop even 1dec. Was great.

Re: How to maintain the mash temperature?

Post #19 made 3 years ago
Shetc. I have used that method to good extent. It works well, I also have a hard foam disc I made to go in the lid.

One other method I have used and it worked is have a small burner under the kettle and set the flame real low, that worked great on a friends system and I copied it, but plumbing it was a pain.
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Re: How to maintain the mash temperature?

Post #20 made 3 years ago
I bought a thick foam exercise mat, cut it half lengthwise then wrapped my pot with two layers (trimmed to size). Every 20 minutes or so I turn the electric stove on for a couple of seconds to make up for any losses.
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