Decoction/rest did I do it right?

[petergriffen]

So for my first non single infusion brew. I followed this below but have one question. I also did this all on the stovetop.

This was my decoction method (5gal with 10.6lb of grain): I doughed in with 3.3gal for 20mins at 132 [Protein] .. then I added another 1.7 gal of boiling water, held temp of 153 for 45 more mins.Then I removed 1.5 gal of mash and brought that to a boil for 20mins. [Sac. Rest] (While the decoction boils does this, does the sac rest just sit there? Because that 1.5g I took out took about 20 to boil and then boiled for 20 so it was more like a 1hr20min sac rest, right?)Returned this to the mash - and then mashed out. I batch sparged with another however many gal of 175 water to get my desired boil amount.

 

[Nateo]

I've seen 122 as the "normal" temp for a protein rest, and Noonan says the protein rest should be 122-131. He does say that at the lower end of the range, polypeptides might be denatured, reducing the body of the finished beer. The protein rest is really crucial for poorly modified continental lager malts.

With modern, well-modified malts, I'll usually only do a protein rest for 5-10 min to avoid excessive polypeptide degradation.

Long sac. rests aren't a problem. It just gives the enzymes more time to work. During boiling you might liberate additional starches, so I'd let it sit for another 15-20 min after adding back to the mash, before mashing out, to make sure any new starches are converted.

 

[ReverseApacheMaster]

You did an infusion-decoction hybrid mash. Typically when you do a decoction mash you use the decoction process for each increase in temp. You don't necessarily have to do it that way.

Depending on the beer, you can also make a rest at 149-153 and use a decoction to bring the mash up to the upper 150s. I think this is what you intended to do? If so, then it is a problem that your rest at 153 went on for so long. It's highly likely that conversion was complete after 80 minutes so you didn't get much out of the decoction.

You actually want to pull the decoction out at the start or mid-way through the rest so that by the time the first rest is done the decoction will be added at the end of that first rest to raise the temperature to the next rest. So in your case, you should have pulled the decoction after 5 minutes into the rest at 153 so that after the 40 minutes of working the decoction you are adding it at the end of the 45 min rest at 153.

Also, it's not necessary to boil the decoction for 20 minutes. 10-15 should be enough.

Have you taken a look at braukaiser's stuff? It's very helpful info about decoction mashing.