overly sweet Moose Drool

[Banjo-guy]

Why does my Moose Drool recipe taste cloyingly sweet?

I scaled the Caribou Slobber recipe from Northern Brewer. This is the first time that I oven mashed. My kettle went into the oven at 153.00 and the oven was set to 170. I can't go any lower. I left the oven on for the whole 60 minutes. I didn't measure the mash temperature coming out of the oven. I mashed about 4 gallons of water plus grain in a 9 gallon pot. There is a lot of dead space and Im sure the temperature went up but I didn't record the final temperature.

Would my mash be the problem?

I keep my mini fridge at 65 degrees and it didn't go more than a degree or two higher during fermentation.

I ended at FG 1.022. The OG was 1.073

What happened to make it almost undrinkable?

Screen Shot 2014-06-02 at 10.30.08 PM.png (107.45 KiB) Viewed 527 times

[swenocha]

I'm going to say high mash temps led to alpha-amylase activity, leading to unfermentable sugars/starches, leading to a sweet beer with a low abv. Beta-amylase, the fermentability enzyme, likes 140°-149° temps, while alpha-amylase works at 155° and 158°. Damn.... I retained from the Chem of Beer course...

Did you leave the oven on for the mash period? The only time I've oven mashed, I set it to lowest setting (170 here as well, I think), turned it off, and then put the pot in to mash.

[Banjo-guy]

The fermentation chamber was set at 65 degrees.
I lefty the oven on for the mash. I think the temperature of the mash went higher during the 60 minutes. I should have recorded that .
I think that will give me a beer with more unfementable starches but it would it leave me with a sweeter beer?

[Beer-lord]

I did the NB version (ingredients bought locally) in August of 2012. I used the Windsor yeast and wasn't pleased with it. But, the SG looks rather high. Theirs calls for and SG of about 1.052. I hit 1.055 but finished too high as well and only got to 4.6%. Mine was not overly sweet but was a tad bit caramel-y. I planned on doing this again but never did.
Looks like that's only 69% attenuation which is a bit under where is should be and there's the sweetness.
I would have to guess mash temperature may have caused the problem as well.

[swenocha]

Noticed I said "high fermentation temps", when I meant "high mash temps" in my initial comment. I corrected it...

If the oven was at 170 during the entire mash, then I think you've found your culprit...

[Banjo-guy]

I see that my screen shot cut off the OG of 1.073. It ended at 1.022. That must be it. I'll to check the recipe and see if I put it into Beersmith correctly.

It looks like something is off.

I added too much dme and that explains the higher abv.

I thought that you meant mash temp

That must be it.
I still haven't found a good way to hold my mash temp.
I generally wrap a sleeping bag around the kettle and put 2 towels on top of the lid. I usually drop about 4-5 degrees by using this method. My kettle is a little too big and the temps are not staying constant with the low water mass. That why I tried the oven mash. Should I have shut the oven off and forget about the mash until it is over?

I am using biab. I might start using a mash tun if I cant't work this out, or maybe a smaller kettle. I brew 2.5 gallon batches in a 9 gallon kettle.

[swenocha]

Turning it on at 170 for 10 min and then turning off before putting the pot in was the method that I was told for when the oven will not go low enough, and it worked reasonably well for me. I remember that I had to turn it back on about midway to bump the temp a touch, but otherwise it held fine... right in the mid 150s...

When I was countertop mashing, I tried a few methods. The best and easiest one was what you described... I simply wrapped the pot in blankets off of the burner and it held reasonably well. I also mashed in a small cooler on the countertop once, and that worked fine, but I didn't see any advantage to that method over the blanket method, and it took an extra transfer step, so I stuck with the blankets. I now mash in my electric turkey fryer, so it's been a while since I was regularly countertop mashing, though I did for the one-gallon test batch I did for Emma's recipe book (that was the oven mash).