10 Gallon Cooler - Mash Tun - Temp Problems

I started with all grain brewing at the beginning of the year. I was making 3 gallon batches and using a 5 gallon Igloo cooler for my mash tun. The strike temps I was given by iBrewMaster seemed to work spot on for my mash temps. Now, I upgraded to a 10 gallon igloo cooler and I am having trouble hitting my mash temps based on projected strike temps from iBrewMaster. This seems to be most prevalent on the saccharification rest. I went to a 10 gallon in part because I did not have enough room to do high gravity beers and multi-step infusions. Any suggestions on how to adjust my temps. I am coming in about 6 to 8 F below.

My current solution is add additional hot water or take some thin mash and decot to bring the temp up. This is a pain. Help me avoid going back to smaller batches...

Have you tried preheating your mash tun with a gallon or so of boiling water?

If not, try it and dump the preheat water before adding grain and strike water. A preheated tun will remove less heat from your mash than one which is cold or at room temp.

The software should have a setting for the mash tun heat capacity that you will need to adjust, as well as the deadspace numbers. Make sure that the equipment in it matches your equipment... The other issue might be that you aren't setting your grain temperature correctly and are now using more grain, so you are getting a bigger error.

I don't have iBrewMaster, so I can't tell you how to fix this, but this is definitely a feature available in the competition (BeerSmith, etc).

It's seems your answer is in your statement. Increase your strike temps by 6-8F. You should also be preheating your mashtun. This is where I suspect you're losing your degrees. Next batch, try increasing your strike temp by 10°F and pour into your mashtun. Then close the lid for 10-15 minutes. Then open the lid and allow it to cool to your strike temp. Finally, dough in and see if your mash temps remain more stable.

I always add the water to my mash tun first at about 5F - 10F degrees above my strike temp and let the water cool down to my strike temp. Then I slowly add grains while stirring into the water.

This is what I use for my calculations:
http://www.brew365.com/mash_sparge_water_calculator.php

*Note, you do not know your Mash Thickness (aka qts water/lbs of grain) so leave it at 1.33. After it calculates the mash water needed in gallons, multiply the number by 4 (4 qts = 1 gal) and then divide by your lbs of grains. You will then get your Mash Thickness which you can add in to the equation. This will then change your Mash Water needed so you have to calculate again and maybe even one more time to the get the correct thickness associated with your water needed.

Hope that helped.

dyqik - how do you establish your grain temp. I am definitely not adjusting this setting in the software.

I'll try preheating on my next batch. Finished for today, with my previously mentioned work around. I have a nice belgian dubbel sitting in primary.

Thanks all for your suggestions.

I know i loose 3 degrees to heat my cooler, so my water will be strike temp+3 degrees. I let it sit in the cooler to preheat for about 10 minutes then remove the lid and add grain or let the temp drop a degree or two if needed before I add the grain.

deadboy182 said:

I started with all grain brewing at the beginning of the year. I was making 3 gallon batches and using a 5 gallon Igloo cooler for my mash tun. The strike temps I was given by iBrewMaster seemed to work spot on for my mash temps. Now, I upgraded to a 10 gallon igloo cooler and I am having trouble hitting my mash temps based on projected strike temps from iBrewMaster. This seems to be most prevalent on the saccharification rest. I went to a 10 gallon in part because I did not have enough room to do high gravity beers and multi-step infusions. Any suggestions on how to adjust my temps. I am coming in about 6 to 8 F below.

My current solution is add additional hot water or take some thin mash and decot to bring the temp up. This is a pain. Help me avoid going back to smaller batches...

Click to expand...

You have more headspace in the biggrr mlt. I cut a piese os Styrofoam to fit my mlt and push it down to right above the mash and i dont lose temp

deadboy182 said:

dyqik - how do you establish your grain temp. I am definitely not adjusting this setting in the software.

I'll try preheating on my next batch. Finished for today, with my previously mentioned work around. I have a nice belgian dubbel sitting in primary.

Thanks all for your suggestions.

Click to expand...

From what I have seen, you simply insert a thermometer in the dry grain and get a reading. Also, I see many guys pre heat the mash tun by pouring a gallon or so and closing the lid before dumping the full mash volume.

+1 for preheating. I've done partial mashes using a 5 gallon mlt. I first pour near boiling water in the cooler then put the lid on and leave it for about ten minutes (start hearing your strike water now). Once my strike water is up to temp I drain/dump the preheat water. Add the strike water and dough in! This has helped me immensely, and there's been tons of headspace (admittedly too much space)!

Also +1 on styrofoam to close off headspace. I haven't done this but have a fellow brewer who does and swears by it.

I just added insulation in my headspace. Made a huge difference in my temp control.

I used two discs of 3/4 rigid insulation that came in green 4x8 sheets at lowes. I cut them with the circle tool on my dremel then stacked them. I then wrapped them with 2-3 layers of aluminum foil.

I plan on doing the same for my HLT

just increase your strike water temp!

deadboy182 said:

dyqik - how do you establish your grain temp. I am definitely not adjusting this setting in the software.

Click to expand...

I assume it's near ambient - I usually buy and mill at the lhbs, then bring it home to brew. It sits in the garage brew space while I set up and heat and treat the strike water, so ambient is probably close, unless it's very hot or cold out.

Preheating the mashtun will help for sure. I keep a couple of gallons of boiling water and cold water for 10 gallons batches for adjusting the temp.

Another trick is to get an inexpensive bucket heater. When I start my mash I transfer my water and add my bucket heater (I also use the bucket heater to heat my water faster). I then wait about 10-mins. I remove the bucket heater and mash-in. I check my temp and adjust after about 5-mins.

I hope that helps.

I always preheat my MLT (HD Cooler) with with a couple of gallons of HOT tap water. I measure the temp of the grain and the temp of the inside of the MLT. I use Beersmith so I enter those numbers and get a pretty accurate calculation of my strike water temp.

Then I add all but about a gallon or so of my strike water and then dough-in, stir reall well and then add the remaining balance of my strike water. I hit my temps all the time and only lose maybe a degree over a 60 -90 minute mash time.

I was having similar issues. Now I heat my water up in my hlt and transfer most of it to my mash tun at 180F, filling the tun 1/2-3/4 of the way. I set my alarm for 20 minutes and let it sit. In the mean time I have a coffee, grind grain, etc. After 20 minutes I expect no more temp drops. I then drain the tun to hlt, leaving enough in the mt for the mash. I dump the grain in all at once and stir. Last 8 batches I have done this way have always been dead on and don't lose a single degree over an hour.

This is for 8-10g batches though. 5g batches lose a lot of heat (normal gravity beer) because of all the dead space in the tun. So instead of buying a 5g cooler I only make 8-10g now. But i'll split the boils in two and make two separate beers with different hops and yeast.

Anyway....the point is that I found simply adding some boiling water wasn't good enough. By filling the tun 1/2-3/4 with 180F water I was able to fix all temp issues.

All, thank you for your replys. I will try preheating my MLT before the next use. I like the approach of dropping in 180F water for 10 to 20 minutes then drain to required level and dough in.

Any thoughts on missed temps for the second step in a multi-step infusion? This seems to be where my temps go off the most...as much as 10 to 12 degrees.

Going to brew an Irish Red in the next week or so...so I will report on the outcome here.

You need to be super careful pouring boiling water into your cooler, thats how you can crack the insides. They arent meant to hold hot liquids, we get by at 150-160 degree's because thats low enough, but 200+ degree water is going to warp and potentially crack your cooler.

There's no need to preheat with such hot water. Put some 150-160 degree water in it and your fine. Hell just dump a gallon or two of the hottest water you can get out of your kitchen/bathtub tap and that will be enough to warm it up significantly.

You should be able to get 130-150 degree water out of your water heater depending on where you set it, no need to take a bunch of water and boil it just to preheat your cooler.

Using Beersmith (or any other good brewing software) is definitely part of my process. As such, I've been very accurate with hitting my strike temps with no preheating. However, I attribute that to three things. First, I adjust for ambient temps. Second, I use a 5g cooler for 5g bathes so its pretty full for the mash. Lastly, I've tweaked the specific heat of my MLT.

Good info here, thus the resurrection. I'm about to brew my first batch using a brand new igloo 10 gal MLT, and have been searching for this info. So for those of you using these coolers, once you have it preheated, how much higher does your strike water need to be compared to your mash temp using room temp grains. I'm making a regular beer with 11 pounds of grain and mash temp of 152. If my grains are 72 degrees and I do a thorough preheat of the MLT, what temp should my mash in water be?

TxBigHops said:

Good info here, thus the resurrection. I'm about to brew my first batch using a brand new igloo 10 gal MLT, and have been searching for this info. So for those of you using these coolers, once you have it preheated, how much higher does your strike water need to be compared to your mash temp using room temp grains. I'm making a regular beer with 11 pounds of grain and mash temp of 152. If my grains are 72 degrees and I do a thorough preheat of the MLT, what temp should my mash in water be?

Click to expand...

It's different for everybody. But you can follow guidelines and then by experience know what temps you need to strike with. For me, I try for ~13-15F higher than my expected mash temp.

http://www.brew365.com/mash_sparge_water_calculator.php

http://www.brewersfriend.com/mash/

Be consistent, take good notes, and then of course make adjustments. I do the same thing every time with my mash tun and grain (both kept in the house anywhere from 63 - 73 degrees year round).

With that said I recently changed my mash tun set-up from a 5gal to a 10gal and had to relearn my process/set-up Feel like a rookie again!

I not sure why you'd preheat your cooler with a separate amount of near boiling water? Why not just heat your total amount of strike water to a set amount above your target mash temp? So if your shooting for a 154°, heat water to 16° above that or 170°. Dump it all in your 10 gal cooler and cover, wait 15 min (water temp will drop about 8°). Then dump your grains and stir (water temp will drop another 8°). Now you're at 154° where you wanted to be. Once you do it a couple times, you'll be able to nail it exactly. Seems a lot easier and straightforward to me.