Mash temps.....rising?

[WhiskeySam]

Beer I made yesterday was about 150-51 after 15 minutes of mash. After 60 minutes, the temp was 153-54. Seems very odd.

Mashing in a 10 gallon igloo. Pre-heated with near boiling water.

Thoughts?

 

[Gartywood]

I think that either your temp probably hadn't evened out at 15 minutes and was hotter than that. I've mistakenly thought that I got a too hot mash cooled a degree or two only to find that 5 minutes later the therm is reading the original temp again.

 

[BrewKnurd]

Your mash wasn't evenly mixed, and where you measured it initially was a cool spot. Throughout the mash, the temps equalized. Always check the temp in a few spots in the mash if you really want to now where its at. That's my thought.

 

[WhiskeySam]

I did that though. My water infusion temp was only 157. I took two readings with two different thermometers in two depths and got 150-51. Finished noticeably higher. Just seemed odd.

 

[BrewKnurd]

I did that though. My water infusion temp was only 157. I took two readings with two different thermometers in two depths and got 150-51. Finished noticeably higher. Just seemed odd.

Well, there's just no way the temp actually went up. So all that's left is the measurements you took weren't representative of the entire volume.

 

[wilserbrewer]

Pre-heated with near boiling water.

Thoughts?

Unless you have some sort of magic mash tun, I think you were not mixed well, or other error occurred. Also, IMHO preheating w/ "near boiling" water could damage your cooler...I would just overheat your strike water 10-15 degrees and let that preheat the cooler...let the temp drop over 10-15 minutes and cool by stirring or adding a few ice cubes to hit your target strike temperature then mash in.

 

[wheels4]

I pre boil all my water strike and sparge. I do the same and add almost boiling to mash tun and wait for it to get to the right temp then mash in. I agree with others ...... you had some cold spots.

 

[Temp81]

My first AG batch I made in my Igloo cooler did the same thing. I put almost boiling water in the cooler for 15 minutes, then dumped off the water and put in my strike water at 170 to get 155-156, stirred in the grain for a good 10 min. Then I took the temp and it was holding at 156. I came back 15 min later and my temp had rose to 160. It got to 165 before I finally got it down again. I think the near boiling water puts too much heat into the cooler. My next batch I just preheated with hot tap water for 5-10 min, then I brought my strike water up to 175, put it in the cooler and left the lid off to let it cool to 170. Then stirred in the grain, hit temps right on the mark, and only lost 1-1.5 degrees over 90 min. Pretty good for a cheap water cooler. Of course at an outside temp of 90+ degrees holding temp is a little easier.

 

[ipso]

I’ve seen this.

I have a standard orange Rubbermaid 10gal mash tun with a SS false bottom. The thing is, if you take a temp, say with a digital thermometer, just after dough-in and a THOROUGH mix - from the center top of the grain - it is my opinion that somehow heat rises to that particular spot of the grain bed. Temp will rise in the center more than if I take an initial temp at the side. Also, I can cover the mash tun tightly and an hour later get a reading 1 degree higher than dough-in (??? - I thought I had the best mash tun in the world!!), there at that center point. BUT, when you mix the mash, your overall temp will decrease 4+°. The lower/upper outer/center temps are vastly different over time, in spite of cooler insulation.

 

[BrewKnurd]

So I take back what I said. if you are really using near boiling water, Then your mash tun could be 190 degrees when you add your strike water. if that's the case, then the mash tun is actually heating the mash.

I always let my strike water sit in the tun for a bit to equilibrate temps with the tun. That's something you could consider trying.

 

[WhiskeySam]

Thanks guys. I'll cool the preheat water next time.

I like my magic mash tun.

 

[daksin]

Just FYI (not super-related to your original topic), but I have seen some data recently that suggests that the most fermentable worts are made by mashing around 153, so if you were shooting for a dry beer, I think you're good to go!

This is related to the dual action of alpha and beta amylase- mashing at an intermediate temperature mimics the benefits of doing a step mash which includes beta and alpha sacch rests separately, that is it creates super-fermentable wort. I'm doing some experiments myself right now and hope to report back soon!