Botched My Partial Mash

I brewed a Stone IPA clone last night and had a stove top partial mash of 2lbs pale 2row and 14oz of Crystal 20. I got my water up to 165 and then put the grain in, but the water dropped too low... down to 148. I turned the gas range on in short bursts to get it up to 154 for the mash. After the temp was in range I had to go upstairs and put my 2 year old to bed. When I came back down my temp was 168 and climbing! I couldn't figure out what in the world was happening.

I dumped a couple cups of cold water in the mash and stirred it up, but I feared the enzymes were already destroyed. The temp was up there for well over 5 five minutes. Come to find out after staring in disbelief, the cast-iron grate over the gas burner was holding a TON of heat and heating the pot up after I killed the flame. I probably got 10-15 minutes of stable temperature before it took off into the 160s. Luckily it was a fairly small portion of my grain bill and I still have 6lbs DME to ferment out, but now I'm afraid the beer is going to be too sweet and FG won't come down. Time will tell, I guess.

Lesson learned, if you're going to stove top mash it's best to remove the pot from the stove completely and put it on a hot-pad instead.

It shouldn't effect the beer too much. Such a small amount of grains and you had about 15 min to convert. Relax it will probably be fine.

I do PM brews and always have a pan of water boiling on the stove and a bottle of water in the fridge to adjust temps with. Only take a little boiling water ladled in to bring the temp up a few degrees. I use a cooler now, but when I use a pot to PM in I just put it in a warm oven to keep it at mash temp. Works great. Just set the oven to it's lowest temp and then make sure to turn it off when you put the pot in. the residual heat keeps the pot warm until conversion is complete.

ChshreCat said:

Just set the oven to it's lowest temp and then make sure to turn it off when you put the pot in. the residual heat keeps the pot warm until conversion is complete.

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I was going to do this until I found out the lowest setting on my oven is 170F. I guess I could just kill the heat, but I bet my oven holds temp pretty well.

If it's 170, just turn it off when you open it up. All that hot air will escape when you open the oven to put your pot in. All you want is the residual heat in the oven. If you turn it off before you put your pot in, it'll never heat it up to 170. You might even have to turn the oven on for 30 seconds or so about halfway through if you really want to keep the temps close. I stick an oven thermometer in there to keep track of the oven temp.

148 is fine - in fact I believe I did the same exact recipe a few days ago and purposely got to 148.

Heat to 170 (like mine) turn it off when it reaches 170. When you open the door to insert the wort a lot of heat will escape. If you are worried just leave it a crack open for a few minutes. remember - it's the 1st 10 to 15 minutes which is important and the wort would gain any temp. It's all good.

as for the brew - the cooler temps will just make it slightly drier with more fermentable sugars and that is a good thing when using 7lb of extract! That much LME will leave a lot of unfermentable sugar in the WORT so cooler is better.

Mine is bubbling away - no need to a blow off yet which is surprising me a little but - we shall see when I get home tonight! Looks like mud! LOL

Yeah I wouldn't have minded if I was just a few degrees off, but 6 degrees is too much IMHO so I wasn't going to leave it at 148. I was too pissed at myself to even bother with a gravity reading and I didn't have any iodine to test conversion. 6lbs of DME is enough to carry the beer so I wasn't worried about the fermentables too much. I let it rest for the remaining 30 minutes at 152 when I cooled it off so if there were any viable enzymes left in there they still got plenty of time to do their job.

ChshreCat said:

If it's 170, just turn it off when you open it up. All that hot air will escape when you open the oven to put your pot in. All you want is the residual heat in the oven. If you turn it off before you put your pot in, it'll never heat it up to 170. You might even have to turn the oven on for 30 seconds or so about halfway through if you really want to keep the temps close. I stick an oven thermometer in there to keep track of the oven temp.

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I did this, but didn't realize my oven was not off until the 30 minute mark. I then turned it off and let set for another 30. Do you guys think I will be OK? my oven temp was 170.