Partial Mash

[Duff]

I'm currently doing my first partial mash and am wondering on the best way to keep the water at a constant 68C for steeping the grains.

I thought about an esky, but wouldn't it cool over 2 hours? At the moment I have a thermometer in a large pot with the grains on the gas stovetop, and am checking every 10 minutes. If it is getting down just under 68, I am giving it a short hit with the burner which brings it up to around 72 before switching off.

Any suggestions?

Duff.

 

[johnno]

duff ,
I found having the griller on underneath on low keeps it at around 66 on my stove.

 

[wardy]

duff, it's surprising just how good the old esky is. I am using a very old one, probably about 15 years old (so it's insulation has probably deteriorated somewhat), and it still holds good temperature for over an hour. I start with water at about 74C. The minute i add it to the esky, the overall mash temp is about 71C. With the lid then closed for an hour, i have a thermometer positioned inside with external readout, and after 1 hour and 15 min, mash temp is 67-68C. You can also throw some towels or a blanket over the esky if you are concerned about the lid sealing properly. Anyway, i find it easier than keeping it on the stove, as there is a great variation between top and bottom of your vessel.

 

[dicko]

Hi Duff,
I used to do what Wardy said but I used to pre heat the mash tun with boiling water from the kettle and have the strike water at 71 deg c and would hit 67 every time. I just used to wrap a blanket around it for the mash time and it would hold temp no worries.
Good luck.

 

[Guest Lurker]

I mashed in a ss pot that would just fit in the oven. Having the oven on and set to 70 degrees used to hold the temp perfectly.

 

[RobW]

If you use an esky and there is a significant airspace above the mash, putting a sheet of aluminium foil on top of the mash helps to prevent heat loss too.

 

[PostModern]

I use a 10 litre esky. Strike temp of 73C gives me a mash temp of 66C. I pre-prime the esky and manifold by filling with boiling water, which I empty and refil with the required amunt and temp of strike water. After dough-in, I wrap the esky in towels and a blanket and lose no more than about 1 during a one hour mash.

 

[deebee]

My bucket in bucket set up loses only a degree or two over a one hour mash. Just heat it up before adding the strike water. Then wrap everything up in a blanket with a belt around it.

 

[dreamboat]

Take note of these strike temps bandied around here, and keep in mind that they differ greatly due to the different water/grain ratios which these guys are using. For example, at a 2L/kg ratio, you would need strike water at around 77C to get a mash temp of 67ish, so the lower strike temps of 71 are for far different ratio's.

FYI I have found that a 2L/kg ratio works satisfactorally for a minimash, but you will get a more stable temperature if you use a thinner mash, ie more water, due to the larger thermal mass. Of course, it is also more difficult to adjust if you get it wrong.

Strike temp = (desired mash temp x (litres water x 0.4 x kg grain) - (0.4 x kg grain x malt temp)) / litres water


I hope that makes sense, just do the brackets first and you should be right.


dreamboat