Controlling Attenuation Through Mash Times

[day_trippr]

I concur, @madhook - I eschew thread proliferation - and welcome to HBT!

 

[madhook]

I concur, @madhook - I eschew thread proliferation - and welcome to HBT!

Thanks, Im looking forward to learning a lot.

 

[jerryh357]

A lot of this is good to know in theory, but isn't necessary or essential for all-grain brewing. Many people (I would assume most) will do a 60 minute mash regardless of the temperature. I'll usually extend my mashes under 152 or so for 30 minutes, unless I'm pressed for time or just feeling lazy. Can't say I've ever really noticed a difference, or one that I can pinpoint to mash time.

I just brewed a porter on Saturday where a one hour mash turned into three hours because I couldn't get my burner working. This is one that regularly finishes at 1.018 to 1.020, with an OG of 1.055. I'll be curious to see if the extra time helps attenuation at all.

I don't think it's about mash time as much is it's about conversion. I have been using iodine to check for conversion, and have seen different times to reach that point, doing the same recipe. Letting the mash temp drop, is not the end of the world, and you may find a better fermentation happens.

 

[doug293cz]

I don't think it's about mash time as much is it's about conversion. I have been using iodine to check for conversion, and have seen different times to reach that point, doing the same recipe. Letting the mash temp drop, is not the end of the world, and you may find a better fermentation happens.

Yes, getting complete conversion is more important than mashing for a particular length of time. The time for complete conversion is controlled primarily by the crush. Finer crushes convert faster (since gelatinization is the rate controlling step in conversion.) More reliable, and more quantitative than the iodine test is measuring the SG of the wort in the mash. Learn about measuring conversion efficiency/completeness in real time here.

Brew on

 

[jerryh357]

Thanks, great article and worth reading!

 

[dtashmore547]

from the late 1970's I have brewed from the big book of brewing by Dave Line, the brew temperature dictates the amount of maltodextrines in the mash, the higher the temperature the more maltodextrines which are less fermentable than Maltose so will influence the final sweetness/dryness of the ale, and so the attenuation, a low mash temperature will give mostly maltose and a light dry fully attenuated ale, conversely a high mash temperature will give a sweeter fuller brew which will take longer to ferment and will not attenuate quite so fully. most important is getting the starch converted and I always use iodine to check for this.

 

[BigFatDad]

I was just looking on homebrewtalk for something like this (original post). I have noticed that I get much better original gravity especially from grains like Maris Otter and American pilsner malt doing a 90-minute or even 120 minute mash. In addition they seem to finish drier as well.
I may have found this out by accidentally completely forgetting I was brewing when I was watching the kids one day. It has now become standard practice to do 90-minute mash for everything brew. I can get a lot of stuff done during that 90 minutes ie cleaning, cooking, running, etc.
I took some mash measurements today during brewing. It was 12 lb Maris, 1 pound C20, 8 oz of c-pils, 18 oz of instant oats. At dough in, I had a gravity of 1.023 which did not really change until 60 minutes when it was 1.043 and my Mash gravity at 90 minutes was 1.050. I also do no sparge so this was with 8 and 1/2 gallons of water that also had 2ml 85% lactic acid, 1g of gypsum and 1g of calcium chloride. This is roughly 70% mash efficiency with 7gals to bk. The math at 60 min is 60% mash effeciency.
The large jump as I approach 90 min has been consistent across at least 6 batches.
Last pils batch I made with 10# pils, 1# carapils and 1# vienna had boil G of 1.043 for again about 70% mash efficiency with 90 min. At 60 min was 1.035 (56% mash eff) . That ones fg prior to kegging was 1.004. Water treatment for that mash was 3ml lactic and 3g cacl2 in 8.5 gal water.