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Mash tun temp. efficiency

PostPosted: Thu Jan 15, 2009 7:52 am
by thebuddrik
I put some bottles soaking in hot water and oxyclean last night in my ice chest/mash tun. I monitered the temp. the whole time. I put enough water to cover the top of bottles standing up. It went in at about 159*. After about 10 min it had gone down to about 153* and from there lost about a degree every 10 minutes. Is this acceptable or do I need to be ready to add some more hot water midway through my mash?

PostPosted: Thu Jan 15, 2009 9:51 am
by redtail28
To be on the safe side yes have hot water ready.
But remember that with gain it much denser than
Glass and will hold some heat. I would pre heat
Your cooler and would expect to lose a couple of
Degrees an hour.
That’s my 2 cents 8)

PostPosted: Thu Jan 15, 2009 12:44 pm
by aleguy
In my thick mash, I haven't had a measurable loss after an hour, but I have a great deal of difficulty getting my mash temp nailed. I wonder if I could adapt my cooler to a HERMS system?

PostPosted: Thu Jan 15, 2009 2:14 pm
by yeastmeister
Agreed, not a fair comparison. Fill that sucker with grain, and you will only lose about a degree in an hour. Its all about density.

PostPosted: Fri Jan 16, 2009 6:23 am
by Mob_Barley
First of all, before you use your cooler for brewing, you need to pre-heat both the mash tun and your HLT. I generally heat the water about 6-8 degrees hotter than the mash temp, so as I pre-heat the tun and it absorbs some of the heat, I can leave just enough water in the tun to dough-in and be at the correct temperature for the saccrification rest.

The remaining water is transferred back to the kettle while the grains are mashing, and heated to 8-10 degrees above sparge temperature, and then transferred back tot he HLT so that an hour later, the HLT will be preheated and at the correct sparge temp to begin the sparge...

Your mileage may vary and a little experimentation will be needed.

PostPosted: Fri Jan 16, 2009 6:43 am
by yeastmeister
While I agree that pre-heating is the generally accepted method, I did about 30 batches and never pre-heated my cooler tun. Yes, it took a couple of batches to tweak my HLT temp to compensate, but it was much easier than that tedious transferring back and forth (this was before I got pumps). Beersmith (and I am sure the others) has a place under details for your mash to put in the grain temp. Set that correctly, and you will be generally within a degree or 2 of where it tells you.

I corrected beersmiths numbers by slowly tweaking the thermal mass coeficient of my tun.

PostPosted: Fri Jan 16, 2009 11:14 am
by aleguy
All I can say is that a 3-degree increase in my strike water temperature translated to a 1-degree increase in my mash temperature. (I've only made two batches AG so far.)

PostPosted: Fri Jan 16, 2009 4:56 pm
by Mob_Barley
I find with the different outdoor temps I brew in, it's easier to start with the mash tun preheated and at the same point each brew session. It prevents having to adjust the temp up with boiling water or down with cold water to get the temp exactly right (or within a degree of your strike temp). It takes about 5 minutes for the mash tun to warm up. I usually just dump the water out the top instead of trying to transfer through the ball valve (which would be tedious and slow). I can add back a little or drain a little via the ball valve to get the correct amount left to dough in with.

Before I started pre-heating, my strike temps were all over the place, even though I put the grain temp, ambient temp, etc. into beersmith.

PostPosted: Sat Jan 17, 2009 10:43 am
by aleguy
I don't know about preheating my tun. I think I just need to learn the peccadilos of my system or put up with it until I get a RIMS system built. I'm not a competitive brewer, so I couldn't care less about reproducability as long as the beer is good.