Result of High.Temp Mash Question Help??

[hbhudy]

I made a Stout about 5 weeks ago and had a mash at about 157 +or- a couple..
The OG was 1074, but the FG was 1036.. I let used 1 package of Nottingham (and it took off like a jet for about 5 days) and was shocked at the FG.. Do you believe the higher FG is due to the high mash temp? The expected FG was 1020ish, but the FG of 1036 was supprising after 5 weeks in the fermentor.

Any thoughts as to the result of the FG1036?

 

[Hammy71]

A high Mash temp may have caused it. I've found that an accurate, calibratable digital thermometer is a must for all-grain. I love this one..

http://www.amazon.com/dp/B00009WE45/?tag=skimlinks_replacement-20

 

[KayaBrew]

157 is pretty high. What was your recipe? You could also have a lot of unfermentable sugar in the wort.

 

[TipsyDragon]

i agree that is probably the mash temp but you should also check to see if its just on the low end of the yeasts attenuation range.

 

[mrmekon]

I made a stout 2 weeks ago. Mashed at 158F on purpose. Also added both maltodextrin and lactose to the boil. OG 1.075. Pitched Notty. Even with all of those unfermentables, I'm at 1.028 right now and still showing a little activity.

Post your recipe, but I think it should be lower. That, or mine has an infection :-/

 

[hbhudy]

I hope it is unfermentables, or I have 5 gallons of bottle bombs.. Thank G. I put these in PET bottles.
Recipe
13 lbs Marris Otter malt
>>1 lbs flaked oats->QuakerOats
>>6 ozs roasted flaked oats (Bake @350 15 minutes)->QuakerOats
1 lb Chocolate malt (350 L)
12 ozs roast barley malt (450 L)
9 ozs debittered black malt
7 ozs crystal malt (120 L)
>>2 ozs ground YukonBlend coffee (Flameout)
>>2 ozs ground YukonBlen coffee (Dry-Hop)
3 ozs lactose sugar (5 minutes)
14.3 AAU Nugget pellet hops 60 min (1 oz @ 13% AA)
2.5 AAU Willamette pellet hops 30 min (1/2 oz @ 5% AA)
2.5 AAU Willamette pellet hops 0 min
>>1/2 tsp yeast nutrient 15 min
>>1/2 tsp Irish moss 15 min
>>Rice Hulls
Nottingham

 

[mrmekon]

Actually, that's probably right. Mine was a partial mash, so all the DME would have fermented out. If I'm at 1.028 with only half of the wort sugars mashed high, 1.036 seems reasonable for the same thing but all-grain.

I think yours is fine, and your lower expected FG just didn't account for your high mash temp and lactose.

 

[hbhudy]

That's what I thought..
Tastes great, but I may not give it out for X-mas gift as the high FG may be a bit much for folks to stomach. I will bring some and let folks try it out for after dinner drinks.

 

[KayaBrew]

Based on my only experience with oats (also in an oatmeal stout), I think they are the culprit in keeping your gravity high. I did a similar thing in that I toasted some of the oats in the oven. My stout never got below 1.025, and after 4 months in bottles, I dumped it out. It was undrinkably sweet. I hope this doesn't happen to you!

 

[red96jeep]

Generally a higher mash temp will result in a beer with a higher FG. I say generally because there are other factors such as yeast that can change that, such as when brewing high alcohol beers and using "frankenyeast" that are suited for dealing with lots of sugars. A high mash temp will result in the formation of unfermentable complex sugars. This results in a bigger body and higher FG as a result of the residual sugars.

Read this
http://www.braukaiser.com/wiki/index.php/The_Theory_of_Mashing

and this
http://www.braukaiser.com/wiki/index.php/The_Science_of_Mashing

If you want to really understand mashing principals and how temperature can affect your brew.