Getting your mash temperature to stay at a certain temp

[the-adjunct-hippie]

Right now I don't really have much invested as far as special burners or dedicated propane units. I do all-grain mashes via stovetop brewing and I have an electric stove. Problem is, I can get a mash temp up to 140, and then once I want it about 150 or so, I touch the knob just a little and before I know it, I'm at 170!!! :smack:

What's the secret to keeping a steady hold temp?

 

[acidrain]

Re circulation and stirring the mash will help distribute hot spots.
Your thermometer is only measuring one spot. If you're measuring 170, if you pull it off the stove and stir it mike a mad man, I'm sure you'll find the temp is not as high as you think.

 

[beernutz]

If you aren't applying constant heat then insulation is another way to hold a steady temp. I used to use an old parka wrapped around my mash tun with a heavy blanket over that which worked pretty well. Later I started mashing in a cooler and now I still use the cooler but have added PID controlled herms coil.

 

[IslandLizard]

This ^ and ^^

Stir well while heating, bring the warmer bottom mash up. Cover while resting.

If the pot fits in your oven, that's another option. Keep an eye on the temps though, oven thermostats are highly inaccurate for mashing purposes. 10°F can make all the difference between a successful mash or a prematurely denatured one.

 

[z-bob]

You didn't say how many gallons you're mashing.

When you get the mash to 150-ish degrees, turn the burner all the way down but not off. Give it a stir every now and then. f it gets more than 2 degrees over your target temperature, turn the burner off. (you can always turn it back on) The more gallons you have, the easier it is to maintain a steady temperature.

 

[the-adjunct-hippie]

Due to limited space and a smaller kettle, I usually make 2.5 gallon batches (fermenter volume) at a time. I'm currently making a Russian Imperial Stout. Water ratio was 1.25 to 1.

I got the water to about 147 degrees before putting the grains in, and then it raised to about 154, which was where I wanted it. I was about to turn the burner to almost off, when I took another reading and it had jumped to 165. I was pretty freaked about it, I didn't want the conversion to stop...so I removed it from heat immediately and poured a half cup of cold water in and stirred it. Got it back down to about 160, and finally down to 155. Left it sit with the burner off for awhile and when I came back to check it after a half hour, it was around 158-160. I'm just upset that maybe that mistake didn't allow for proper conversion.

Another question - if you spike the temperature, let's say it reaches 170 or so, is it all over? Does that mean your conversion is just done? Or can you save it by still mashing at a lower temperature even though it peaked for maybe a minute?

Thanks again everybody.

 

[navethechimp]

The denaturation process is not immediate, so it is unlikely you ruined it. Even when you are in the 150's, alpha amylase is going strong while beta amylase is denaturing, but still working to some extent. High temperatures increase conversion but also denaturation. This is how we have this range of "optimums".

That said, some control will be necessary for repeatability.

 

[balrog]

When I stove top mashed island brewers mentioned wethod was best--set oven to lowest setting "keep warm"" typically 170, TURN OFF OVEN, hit strike temp with water and learn what that has to be for your system, dough in, put kettle in oven .

 

[madscientist451]

I'm assuming your are using the BIAB method? I didn't see that mentioned anywhere.
A couple of suggestions:
- Use the strike temperature calculator on the Green Bay Rackers website
https://www.rackers.org/calcs.shtml
Just plug in your numbers and you'll hit your correct initial mash temperature every time.
Trying to bring the mash temperature up to the correct level using bottom heat is a hassle and will result in overshooting your mash temp, which you've already experienced.
-Go with a thinner mash, like 1.75 qt/lb. The more water water, the more thermal mass, the longer you can hold your temperature.
-Have a Gallon of boiling water in a side pot going. If for some reason you mess up your initial temperature, you can stir in boiling water to bring it up. Also, keep an eye on your temperature as the mash progresses, when it falls 3-5 degrees F, just stir in more boiling water to bring the temperature up. For me, this method works better than adding bottom heat. You can also use this method to perform step mashes. Use the Rest Calculator on the Green Bay Rackers website to determine how much boiling water to use. A 4 cup Pyrex cup comes in handy to measure and add the boiling water. Don't fuss too much with the temperature, if its off by a few degrees, your beer will be OK.
-As others have mentioned, insulate your kettle with an old coat or blankets. If your kettle has head space at the top, you can lay a piece of aluminum foil on top of the mash.
-Perform a test run with your stove. Is it gas or electric? My electric glass top range holds heat for a long time, is it better to move the pot off the burner or leave it there? If you heat a kettle of water to 165F and turn the burner off, does the temp keep rising or stay the same?
Try some different things and see what happens.
-When you get tired of temperature swings and spilling wort on the stove when you pull the bag out, go to Walmart and get a 5 gallon round cooler for about $20. You'll need to add a spigot and a 90 degree elbow for the inside of the cooler. You don't need a false bottom or anything else. Put your BIAB in the cooler and use that for mashing. Pre heat the cooler with tap water before mashing and you won't have to do anything for an hour, just put your grain and water in there and forget about it.
If you are short on space, the cooler can be used to store brewing equipment so it doesn't really take up any more space than you are currently using.
Happy brewing

 

[Raoul_Duke_PhD]

PID controller.

 

[Jtk78]

Here's a thought I had, and I make no claims it's a good one. If you are doing BIAB, maybe get a 5 gallon water cooler and mash in that? Heat your water to strike temp, dump it in the cooler, tie the bag over the water cooler and dough in, stir and cover. They hold temp great.

 

[frozyn]

I got the water to about 147 degrees before putting the grains in, and then it raised to about 154, which was where I wanted it

I would suggest getting your water to strike temperature before adding the grains. I've had great success with the Priceless calculator. Input all your information correctly in the calculator and, chances are, you will hit your mash temperature perfectly if you stir the grains into the water vigorously. Then, follow the suggestions above (oven, insulation, etc.) to keep the temperature consistent.

For what it's worth, I surmised that letting the kettle sit on the open grates of my gas stove top was likely what caused my mash temp to drop by 4 degrees on my first BIAB, despite wrapping it with a big winter jacket. For my 2nd batch, I moved the kettle onto cork hot pads on the counter and, with the jacket still wrapped around it, I lost only 1 degree (IIRC). Both 60 minute mashes, but my water-to-grain ratios were more in the 2.4-2.6 qt/lb range, which helps.