Stout mashed at 148 f?

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stevedasleeve

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So in a series of small miscalculations I ended up with a mash temp of 148 for my stout. I left it, not wanting to mess with it anymore and figured it would be interesting. I have mashed at high temps before to see what might happen but never gone below 150 f. I wonder if anyone can offer me some idea as to what I should expect!


This is for my dry/American/foreign stout I have brewed many times before at 151-3.

5 gallons: 1.063 expected, Maris Otter, flaked barley, black barley and a little malted oats, one bittering addition @ 63 IBUs (Rager) + 1 oz Chinook at flame out.

I am wondering at this point if I should reduce the bittering to compensate for how dry this is going to end up...?
 
I wouldn't change anything regarding IBUs. You'll wind up a little lower on FG, but if you've already brewed this at 151, it isn't going to be that drastic a change. The flaked barley and oats will add body as it is, so it should have good mouthfeel. I like my stouts on the dry side.
 
I have the day so I'm mashing 120 mins or so. This might be a great thing or not - don't ya love brewing?! I actually dislike stout unless it is dry and there are not too many I have had with a decent bitterness without a chocolatey deserty thing. I had a fabulous stout in the UK last month made by Brewdog - Mr. Miagi Stout - at around 6% which had wasabi in it. Got to try that sometime!
 
The wort will be a little more fermentable (which leads to dry!), so I'd imagine it will be fine.
 
The wort will be a little more fermentable (which leads to dry!), so I'd imagine it will be fine.

I am going to do my first all grain this week, so I want to make sure I get it right, are you saying that longer mash time at the proper temperatures will produce more fermentable sugars? What I have read is that lower temperatures will produce more fermentable sugars, but I never heard that longer time in the mash will do the same thing, hope I got it correct.
 
I extended the mash time due to the lower temperature but this is simply to make sure all is converted (also I had things to do.) More fermentable - as in drier and higher alcohol content - is inversely proportional to temperature. I generally mash 151-156 f, this is the first time I have gone below 150.
 
stevedasleeve said:
I extended the mash time due to the lower temperature but this is simply to make sure all is converted (also I had things to do.) More fermentable - as in drier and higher alcohol content - is inversely proportional to temperature. I generally mash 151-156 f, this is the first time I have gone below 150.

I will be interested to hear how this turns out. I just had a similar experience - my friend and I brewed an oatmeal stout two and a half weeks ago with a target mash temperature of 152 but we lost 3 degrees over the course of the mash and ended up at 149. Since then, I've noticed that a lot of the American-style stout recipes posted here and elsewhere have higher mash temperatures, some of them up to 158 even. Our recipe included dark crystal and carapils in addition to the oats - so I'm hopeful they will add some body and balance out what I'm guessing will be a lower than anticipated final gravity.

I'll be bottling this weekend and taking a gravity reading. I'll probably end up drinking a bottle the following weekend, too - I can't help it. I'll report back here, too.
 
A buddy and I made about 20 gallons (two 10 gal batches) of Stout mashed @148...VERY DRY!!!

be prepared to let it age to drive down the bitterness from the roasted malts and hops...you can add lactose to backsweeten it at kegging or bottling to counter the dryness for a dry bitter stout can be difficult to drink...should have plenty of abv punch to it:drunk:!

As far as the time at the lower mash temp, you should still convert in about an hour.

Good luck!
 
I've just gone to doing an iodine test with Iodophor to see if the conversion is complete. It works really well, and is interesting to see it work. I've had a batch convert in just barely a half hour, and a batch I did over the weekend that took 75 minutes. Its worth trying if you haven't done it.
 
Within the generally accepted range of mashing temps, about 148-158F if I recall correctly, the lower end of the range will result in more fermentable sugars than the upper. It has to do with the enzymes that those temperatures activate. As someone else indicated, the longer mash is really more to ensure conversion. I, too, believe one hour is about right.
 
Shaggyt said:
be prepared to let it age to drive down the bitterness from the roasted malts and hops...you can add lactose to backsweeten it at kegging or bottling to counter the dryness for a dry bitter stout can be difficult to drink...should have plenty of abv punch to it:drunk:!

How many IBUs and what percentage of roasted malts in your recipe? I'm curious to compare it to mine so I can decide if we've created a dry monster. Thanks. (And apologies to the OP if I have hijacked your thread.)
 
Ya Focker. Ok go ahead and hijack, I'm finished brewing today anyway! Incidentally I am not worried - 148 will work fine - I was mostly looking for brewers who have actually brewed a 6-7% stout with such a low mash temp. This is my 20th gallon this week so I'll be able to age it quite a while before running out - which was part of the point at brewing this particular beer.
 
Update on this FWIW: the stout is great. Recipe below:

10 lbs MO
2 lbs flaked barley
1 lb black roasted barley
1/2 lb oat malt
1 oz Warrior @ 60 mins for 65 IBUs
1/2 oz Chinook at flame out

Mashed 148 for 120 mins

US-05 fermented 4 weeks @ 64 F, cooled to 36 for 3 days before kegging. I think I'll do this again, same mash temp. This is good now and I am sure will mellow out very well.

OG 1.063, FG 1.009 (!) 7% ABV
 
I know that you posted the original thread back in November, but I thought this video might be useful to you. Bobby M does an awesome job of explaining the process of saccharification, and how both alpha and beta amylase enzymes are more effective at different temperatures. It's good information to absorb, and emphasizes the importance of mashing at specific temperatures to obtain a specific beer profile, or allow more or less fermentable sugars to give a higher/lower final gravity. If you know all this, just ignore the video :p I just think it's a great visual way to understand what is explained in so many books:
 
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Thanks! Several stouts later I am mashing at 148 as a mater of course. Turns out its just the ticket for the dryness I was looking for in a big black beer. My most recent is maybe the best beer I've ever tasted!
 
Thanks! Several stouts later I am mashing at 148 as a mater of course. Turns out its just the ticket for the dryness I was looking for in a big black beer. My most recent is maybe the best beer I've ever tasted!

Thanks for the follow up. Going for a lower mash temp on a stout next time brewing.
 
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