Slow Cooker Mash?

[dnr]

I am only on extract, but want to switch to partial and all-grain. Limited space and lack of a large kettle got me to think about using a slow cooker to mash.

I have seen one guy from Australia doing it but am curious if anyone here has and if it's worth doing.

Thanks.

 

[brownni5]

I haven't heard of this hack. My slow cooker only has "low" and "high," and while I've never checked the temperature of either, I suspect even the low is too high.

If you can control the temp between 145 and 160 F, I suppose you could mash. Volume might be the limiting factor, but they do come in a range of sizes.

If you're able to do extract, you probably have all the equipment to do all-grain, save for maybe a mesh bag, at least at a reduced scale (under 5 gallons?).

 

[VikeMan]

Using a slow cooker for mashing would be kind of like using a steam jacketed mash tun, in that the temperatures would vary from the centers to the sides/bottom. If I were going to try this, I would...

- use the cooker on its very lowest setting -AND-
- use an external temperature controller, with the probe in a thermowell in the mash

I have actually sort of done the above with mini-mash experiments, where the "mash jars" were submerged in water, whose temp was controlled the way I described. But in my case, the water around the jars served to buffer the "direct" heat from the cooker.

In a steam jacketed mash tun (without stirring), the liquid near the sides can literally boil, while the middle of the mash is at say, 150F. So these tuns normally have a way to stir the mash. I don't think a slow cooker heating on its lowest setting would be anywhere near that problematic, but I do think there is the possibility of uneven mash temps throughout the mash.

 

[RM-MN]

How long do you expect for it to take to complete the conversion of starch to sugar? An hour? More? Less?

With my experimentation the time it takes to gelatinize the starch is the controlling factor. Conversion takes very little time. Mill your grains fine and conversion is quick. Do a poor job of milling so the grain particles are quite large and 90 minutes may not be enough.

Here's an experiment for you to try. Buy some povidone iodine (the red stuff). Buy a pound of malted barley (two row or 6 row). Crack 1/4 pound of the barley with a rolling pin or beer bottle. Put another 1/4 pound in the blender and really blend it so it is like flour.

Heat a little less than a quart of water to 160F. Stir in your cracked grains and take out a little of the grain every 5 minutes and apply a drop of iodine. When the iodine quits turning blue, conversion is complete for the purposes of this experiment. Record the time.

Now again heat the same amount of water and stir in the blended to flour barley. Repeat the iodine test and see how long it takes for conversion except this time do one test every one minute. Compare the times.