Mash Temp Way off, cant figure out why

[dirtyb15]

Just trying to figure out what happened on my last brew. Using a round 10gal cooler, same grain bill i have used maybe 3 or 4 times in the past. I have always hit my target mash temp within 1 degree or so. This time i was shooting for 152 and after stirring in I was at 160. I added some cold water to get me back down, but just can't figure out why i was so off this time. Only thing i can think of is the warmer weather, grain was warmer, mash tun was warmer etc.. but wouldn't think it would cause that drastic of a change. Thought maybe the HLT thermometer too, but it is reading the same as the mash tun and boil kettle today at ambient temps. Just curious if anyone else has ever seen something like this? Hoping its just a fluke.

 

[day_trippr]

Thermal mass matters. Many of us use brewing software to calculate strike water temperature, taking the temperature of the tun and grains into account...

Cheers!

 

[d3track]

Weather, tun and grain temps can give me nearly 6* swings. The cooler seems to absorb more initial heat.

 

[Paradigm]

Before I mash in I store my metal thermometer in the grain and calculate my strike water based off that. Grain temp actually matters a lot.

 

[revco]

I see a lot of variation over the year, sometimes as much as 5-10 degrees in the winter and shoulder months. Your grain temp, cooler temp, fitting temps, and basically anything that touches that wort can have more or less of an impact. Since you're doing mostly the same recipe, you probably don't have the problems I have, but I see a good bit of variance even in the amount of strike water vs. grain I'm using from recipe to recipe.

I spent quite a few brews (over 10) trying to train my system's results into software and eventually just threw my hands up and gave up with "close enough." I spent hours researching, adjusted almost every parameter in software that I could think of, took precise measurements of equipment temps, calibrated my equipment and so forth to try and dial it in precisely. Anymore, I just always aim a bit high and just a hair thin, using cold water to bring it down to temp with precision. (That's easier for me than raising temps.) Once I switched to this method, I was much happier with hitting my targets from batch to batch and can get/maintain temps to literally a half degree easily. I haven't had really any noticeable issues with a wee bit of time mashed high, so long as I work relatively quickly to get to desired temp.

In theory, all this stuff should be relatively predictable and the software does a decent job at estimating. But, it's still an estimate when it comes right down to it and there's a lot of variables in our systems and practices that can have an effect.

Good luck! That's just my method, others might have further insight.

 

[dirtyb15]

Thanks everyone for the replies. I figured the grain/tun temp would affect the mash temp some, just not by 7-8 degrees. Guess i was wrong .

 

[pricelessbrewing]

Tun temp definitely, but changing the grain temp 10 degrees will only affect your strike temp like 2 degrees. You can either find out how much temp loss is due to your mash tun, 6-7 sounds like a good estimate, or you can preheat the mash tun to 150~ before draining that and reheating the water to strike temp.

 

[whoaru99]

I started all grain a few batches ago. What I do, at least for the initial infusion is heat the water several degrees high, put the necessary amount of warm/hot water in the cooler, then let the cooler warm up and the water temp to come down to temp, then add the grains (with their temp factored in).

 

[Zippox]

I just always aim a bit high and just a hair thin, using cold water to bring it down to temp with precision. (That's easier for me than raising temps.) Once I switched to this method, I was much happier with hitting my targets from batch to batch and can get/maintain temps to literally a half degree easily. I haven't had really any noticeable issues with a wee bit of time mashed high, so long as I work relatively quickly to get to desired temp.

I just want to make sure that it's true that you can have the grain mashing at too high of a temperature for little bit as long as you work quickly to adjust it. Can anyone else confirm this method of heating water up higher than you should then cooling mash temp down with cold water?

 

[day_trippr]

Striking high is not an optimal situation wrt denaturing enzymes, better to be on the low side, imo...

Cheers!

 

[revco]

I think of it like this with batch sparging. When we add our strike water, no matter what it's always too hot in there for some of the grain before we get a chance to add the full grain bill/stir the mix and allow temperature dynamics do their thing and bring about a common temp. Another minute isn't going to kill anything. The mash process takes at least 15 minutes, usually 30 or more minutes, to fully convert the available starches into sugars. Depending on the temps involved, what will happen at that slightly higher temp is maybe a little bit of higher levels of alpha amylase conversion compared to beta amylase conversion at the (presumed) desired lower level. Will there be a technical difference? Yes. Will it drastically change the character of the beer? Not really.

Now, I'm not saying go hog wild and strike to 170 here. But, what I am saying is if you are pretty sure that, say, 168 strike will get you to 152 in your system...it's not going to hurt the beer and strike at 172 to get 156, then drop with cold water to 152. The overwhelming bulk of the conversion will happen at the desired temp. Even if you were extremely high, say 170, it still takes a while to completely denature enzymes...you'd have more impact, but you wouldn't prevent conversion entirely if you correct it quickly.

It's not ideal, but for me, a low mash temp is a pain to deal with. Essentially it's emergency decoction time, which is even less ideal because you have stuff mashing at lower temps while you're trying to correct the entire tun's temp. It's a 5+ minute process, compared to less than a minute to add cold water. It's really just a way for me to get better repeatability and consistency with varying conditions because my brewhouse (garage) isn't temp controlled and I see variance when it's 30 degrees vs. 70 degrees.

 

[pvpeacock]

I agree with revco and use the same process. I keep a pitcher of cold water in the refrigerator and add it as needed once I mash in to get to my target mash temperature. Takes less than a minute using a paint stirrer on a cordless drill to hit the right temperature throughout the mash tun/cooler. I tried using software to calculate the perfect temp for the strike water, but realized it took more effort to take the temp. of the grain and the mash tun and calculate heat absorption rates based on the material of the mash tun (plastic) etc. I may end up mashing a little thinner than I should, but have not noticed any problems as a result.