Controlling mash temperature with induction heater

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Frozenbeer

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Hi all,

I'm new here and basically new again with all grain (not having brewed for 15 years...). I wonder whether someone could help in improving my mashing. I have an induction stove and a stainless steel pot. During my first two batches I had big problems in keeping the temperature steady. It goes up and down quickly as soon I switch on or off the heater.

Unfortunately I have limited space and the need to keep it simple. I assume I could still find some solutions to improve the temperature control.

During my last mash phase, the iodine test was still negative after one hour and half... eventually the beer (an IPA) turned out to be drinkable... but the mash was far from optimal...
Thank you guys in advance
 

madscientist451

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The problem with adding bottom heat is that you'll have temperature swings.
I started BIAB on my electric (open coil) stove, went to BIAB in a round cooler, and now am back to BIAB with a ceramic top stove.
The ceramic top stove holds heat for a while, so that helps.
But having a large thermal mass helps as well. Smaller brews are going to cool off faster.
So my minimum size is 3.5 to 4 gallons and that much grain and water will hold temperature pretty good if I wrap up the pot in an old coat.
Avoid opening the pot to check the temperature, just leave it alone.
But if you really feel the need to fuss with it, have some boiling water ready and check the temp after 1/2 hour and stir in some boiling water to bring your temperature back up.
Here's a calculator to determine how much boiling water to add: (use the "rest calculator")
 
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Frozenbeer

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Hi,
thanks both. I'm actually not brewing BIAB. I put the grains in the water and filter them afterwards. I could try BIAB, even if I have to see how to lift the bag because I assume it should not lay on the bottom of the pot during mash (...correct?). Would BIAB affect the mashing prosses and improve the temperature control>?

I also have the limitation of the size of the pot (small stoves and kitchen space in the flats in Helsinki...), so I can only brew small batches.
But I can try to keep the pot closed with the heater off (if I turn it on even to the minimum the temperature rises..)
 

RM-MN

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Have you seen a dog chase its tail? Trying to control mash temp by adding heat is a bit like that as it will get too cool, then too warm, then too cool, etc. Instead you want to control the temperature by insulating the mash tun.

The mash temp is only critical during conversion from starch to sugar and that conversion time is proportional to the size of the grain particles. Smaller particles gelatinize faster so the conversion is over quickly and the falling temperature isn't much of a concern. BIAB will allow very small particles without a stuck mash so that will help you but only if you have your own mill so you can take advantage of that. I use a Corona style mill and have it adjusted to make the smallest particles possible.

The bag laying on the bottom of the pot won't be a problem if you don't try to add heat.
 
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background: I typically brew BIAB (double crush) or DME+steep targeting 12 pack (1.5 gal) and occasionally 24 pack (3 gal) at packaging time on an induction cook top.

I also have the limitation of the size of the pot (small stoves and kitchen space in the flats in Helsinki...), so I can only brew small batches.
As @madscientist451 said (above), larger amounts of grains help stabilize the mash temperature.

During my mash, the kettle sides are wrapped (two layers) with Reflectix, the lid is on and covered (two layers) with a bath towel. For my common mashes, this will hold the mash temperature in range for 30+ minutes (with a drop of around 2° F over a 60 min mash). With 5 lb grains, mash temp is consistent for 60 minutes.

Opening the lid seems to cause a drop of about 1° F. The kettle lid has a steam vent - and the vent is large enough for the probe for my my digital thermometer / alarm. If I were to take a mash pH sample, I would typically accept the temperature loss (1° F); I could also add 1° F to the strike temperature.

For less than 3# of grain, people talk about using a preheated oven to hold the mash stable. Heat the oven to 160° F, turn off the heat, insert the mash, let is sit for 30 to 60 min.

During my last mash phase, the iodine test was still negative after one hour and half.
Without knowing your mash size and temperature ranges, this may be due by the swings in mash temperature. Or it may be a separate problem (grain crush?).
 
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