Mash Temp Drop Question

[Jiffster]

I use a 10 gal igloo cooler for my MLT. Usually no drop or very minimal in mash temp.

Today I mashed and got my temp to 150F.

I checked the pH at 10 min - stirred before checking.

I then calculated and (About 5-8 minutes later) added required lactic acid to bring pH to target and stirred the mash well.

When the mash was done and I checked the temp it was at 140F. Mash pH was right on.

I'm guessing this happened as a result of opening twice and stirring.

How do you manage your temps when checking and adjusting pH without adding heat?

 

[MagicMatt]

This may not be the answer you're looking for, but without adding heat in some form I don't think it's possible. I would suggest to learn your system and get to where you can consistently predict your mash pH so you don't have to adjust it on the fly during the actual mash.

It is a bit hard to do this on the first time brewing a recipe, but you can usually draw conclusions from other similar (by grain bill) brews you've done and use that as a baseline. I use both BrewnWater and Brewer'sFriend to calculate my mash pH based on starting water, grain, and salt additions. Over time I've gotten to know how my real-world measurements stack up against the predicted pH.

So basically I never adjust my pH. I always measure, and but if it's off all I do is note it for the next time I brew this beer, so I know how to adjust the salt additions or acid malt additions, etc. (Note that if there was an extreme difference from what I desired, like say it was 6.5 or something, then yes I would make and addition and just accept I will lose some heat).

Also, could there be a chance that your thermometer is off? I always use 2 thermometers (one digital, one analog) to measure my mash. The analog stays in the MLT during the mash, and the digital is near-instant so I get a verification (sometimes there is a couple of degrees difference between the center and nearer to the sidewalls, but this can be due to hot spots, etc, so I usually just take a few readings and average them).

 

[Jiffster]

I'm confident in the thermometer accuracy. It's a Thermoworks.

Hopefully conversion took place in the right temp range before dropping to 140-141.

I guess practice makes perfect huh?

Thanks for the response and describing your process. I'll aim for that goal as well.

 

[day_trippr]

fwiw, here's how I used to solve the "lost heat" cooler MLT mash problem when it arose.

First, full credit for the following goes to FlyGuy and his "easy steam infusion mash" thread where he showed how to rig up a pressure cooker to restore mash temperature in a cooler MLT. When I was brewing outdoors in winter in my pre-HERMs days with my 10g Rubbermaid this saved the bacon countless times.

Here's my implementation of his idea, based on a 24 quart PC I picked up at a recycle/thrift shop for all of $5 almost 10 years ago.



The manifold is 3/8" copper tubing with a 1/16" hole every inch or so, tubing is silicone. I fitted and silver soldered short sections of the copper tubing around the perimeter and slipped silicone tubing over them to help position the manifold in the tun while keeping the stubs from gouging the MLT lining. Note the arched bend in the foreground.



A conglomeration of brass to get the job done. I drilled and tapped the thick aluminum lid to take the 90° fitting, then added the ball valve and a compression fitting to get to the tubing.




Manifold installed, the arch crosses over the ball valve/dip tube. I could actually install this even with a totally full tun when necessary just by positioning it in the right rotation then pressing it down with my paddle.



I would put a little more than a 1/2" of water in the cooker, seal it up, get the steam up to 30psi or so, stuff the manifold into the tun then open the valve about half way and stir like the dickens. I could bring the mash up roughly 3 degrees per minute at full blast. Once the mash was back to target I extracted everything and sealed the tun again.

The thing made an awesome rumbling/groaning noise in use - the first time I did a hydro test the Spousal Unit came running to see what the heck was going on

Not advocating, but I love gadgets that solve problems, and this thing sure did the job in a hurry, and never caused any issues with the mash...

Cheers!

 

[wilserbrewer]

I have found if you mash in and take a temp immediately you will get a false high reading as the grain is still absorbing heat. For an accurate mash temp I find it critical to stir very well, wait a few minutes and stir again and then check temp. There is a drop prior to the mash temp stabilizing if you measure temp immediately.

 

[BearHillEast]

If you're using a cooler then take a few gallons of water and bring it up to around 180 degrees and put it in the cooler before you start.

The job of the cooler is to insulate, which requires absorbing some of the heat which can result in an overall loss. It will hold the temperature longer, but at the lowered temperature.

Pre-heating the cooler will get it up to temperature before you start.

 

[olotti]

Fwiw I add all my mineral and LA additions to my water before I add it to the mlt then that way when I add the grain I stir down till I get my desired temp then just close it and let it be. I do 90 min mashes and in my 10 gal igloo same as yours I'll get maybe 1/2-1deg or no drop in temp by the end of the 90 min mark. You can lose a lot of heat if you stir like you did especially if it's colder outside I've done that in the past and the colder ambient air temp just sucks heat out of the mlt so it's best to just leave it closed when u hit your desired temp, you can still pull a sample for ph check but don't stir next time that may help.

 

[Lefou]

I put about 2.5 to 3 gallons of hot water with StarSan in the mash tun and let it sit, then get my strike water hot.
That makes my stainless boil kettle nice and shiny and sanitizes the mash tun.
Pre-heating the mash tun is a good idea. I did this same thing with my Igloo 10gal. today and my mash temp was right between 150F and 160F.

 

[olotti]

I put about 2.5 to 3 gallons of hot water with StarSan in the mash tun and let it sit, then get my strike water hot.
That makes my stainless boil kettle nice and shiny and sanitizes the mash tun.
Pre-heating the mash tun is a good idea. I did this same thing with my Igloo 10gal. today and my mash temp was right between 150F and 160F.

This is also great info I do the same. I'll dump half my mash water into my cooler to preheat it then when I hit my temp and this temp can only be known by using your system enough to to where you know at what temp to get your mash water at that when u add the grain it'll hit x temp when u add the grain you'll hit your desired mash temp.

 

[Jiffster]

I dumped the water in the tun at 205F. Swooshed around and let it settle to strike temp of 166. Then I coughed in and stirred thoroughly. Took about 8 minutes of stirring and adding a handful of ice cubes to get the temp down to 150.

I think the issue drop in temp resulted from checking pH and treating.

 

[RM-MN]

I dumped the water in the tun at 205F. Swooshed around and let it settle to strike temp of 166. Then I coughed in and stirred thoroughly. Took about 8 minutes of stirring and adding a handful of ice cubes to get the temp down to 150.

I think the issue drop in temp resulted from checking pH and treating.

Conversion starts immediately after the grains get wet. Any pH change you want to make should be done before you add the grains. By 10 minutes into the mash a great deal of the conversion is already done and you did it at the wrong pH level. Same goes for the temperature. Your 8 minutes of stirring aided in getting the conversion so you did a good part of the mash at a temp higher than 150. Use the calculators to choose the proper strike temp and don't add grains until you are there.

By the time your mash temp fell to 140, your conversion was probably done so quit worrying about the temp drop.

 

[dwhite60]

What was your recipe? Be interesting to know how much grain you had in that cooler.

All the Best,
D. White

 

[MagicMatt]

If you're using a cooler then take a few gallons of water and bring it up to around 180 degrees and put it in the cooler before you start.

The job of the cooler is to insulate, which requires absorbing some of the heat which can result in an overall loss. It will hold the temperature longer, but at the lowered temperature.

Pre-heating the cooler will get it up to temperature before you start.

Preheating in the manner you specify isn't necessary. Just adjust your strike temp to allow it to "preheat" the MLT prior to doughing in. For instance, let's say your MLT is at exactly 150 (your desired mash temp), this would mean your strike temp should be about 156°F (personal experience, ymmv). Well if your MLT is starting off at say 70°F instead, then you just need to increase the strike temp a bit to compensate. For me, that number is always 11°F more than my desired mash temp. So if I'm aiming for 148°F, I get my strike water to 159°F and dump it in my 70°F MLT, let it sit for about 4 or 5 minutes to absorb the heat, and once it is around +6-7°F from my mash temp, I dough in. Since I've figured this out, I haven't missed my mash temps yet (and no need to heat additional water unnecessarily).

I put about 2.5 to 3 gallons of hot water with StarSan in the mash tun and let it sit, then get my strike water hot.
That makes my stainless boil kettle nice and shiny and sanitizes the mash tun.
Pre-heating the mash tun is a good idea. I did this same thing with my Igloo 10gal. today and my mash temp was right between 150F and 160F.

Just curious as to why you sanitize your MLT? Hot side equipment doesn't need to be sanitized. Not saying you can't do it (obviously), but just don't see the benefit (and the need to waste Starsan). Also, it's really not a good idea to use Starsan in a hot water solution - since it's an acid solution, I believe heating it causes the pH to rise, making the solution less effective. From the warnings I believe it recommends ambient temps only.

 

[madscientist451]

I dumped the water in the tun at 205F. Swooshed around and let it settle to strike temp of 166. Then I coughed in and stirred thoroughly. Took about 8 minutes of stirring and adding a handful of ice cubes to get the temp down to 150.

I think the issue drop in temp resulted from checking pH and treating.

I lay a piece of aluminum foil on my mash to help keep the heat in.
Also, I keep a small pot of almost boiling water handy and if I some how miss my desired mash temp I can quickly add a measured amount to bring the temperature up. Using this step mash calculator, (labeled REST calculator here) it works every time:

http://www.rackers.org/calcs.shtml

Using the rackers strike temp calculator, I seldom miss my mash temp anyway. I mash in, take the temp, put the foil and lid on, and an hour later its within a degree or two.

Where you mashing inside in a warm environment? Or outside when it was cold?
A 10 degree mash temp loss seems excessive.
How big a batch were you brewing? What was the qt/lb water/grain ratio? How full was the Tun?