Tried modified decoction

[ScottG58]

I brewed with it in the 30s in the garage today. BYO Stone IPA. The recipe is basic. Two row and crystal 40.

Mash temp was 149. I hit it. 15 minutes later 147. I get a wild hair. Rather than dilute the mash to heat it, pull a decoction. I ended up pulling 3 two-quart decoction before I had full conversion.

I just read on BYO that decoction with well-modified grain denatures proteins in the grain necessary for head retention.

Anybody have experience with this to tell me what to expect? I've done decoctions before but with Munich or Vienna.

 

[VladOfTrub]

Did you only pull mash liquid to boil? If you did, don't until after conversion, to reach mash out temp. If you pulled mostly mash for the decoction, did you do a protein rest in the decocted mash? Or a protein rest in the mash tun? If not, don't worrying about it. Protein rest temps are well below 147F. You should know that if you are doing decoctions. If you pulled mostly mash for the decoction, did you allow it to convert before boiling? If not, try it next time. Worry if the pH was out of whack when you boiled the mash. Munich and Vienna are high modified with just a little less diastatic power than pale or lager, due to the way the malt is kilned. Floor malts are lower modified. Malted and kilned at lower temps than high modified and are more suitable for decoction. When the topic that a protein rest isn't needed with high modified malt comes up, it is only one line taken from a 50 page text. There's more to it. British malt is modified to the point that a protein rest will thin the beer, drastically. The protein rest should be omitted. But, it would be very stable beer, if a protein rest was employed. Using Continental malt, it will take about 2 hours for a protein rest to overly thin the beer. There are branching and debranching enzymes being employed during the rest, even though the starch may not be completely gelatinized. There are other enzymes besides alpha and beta in malt, that improve the final product. Use them. There might be a little more to brewing beer than pouring hot water on grain and waiting for something to happen. Look into Weyermann's recipes. Many call for a protein rest using their high modified malt. If you are worried about keeping spot on conversion temps and you don't want to infuse hot water or pull a decoction, buy a mash tun that you can fire. Even if you used hot water to jack up the temp, a thin mash converts quicker. The very few times I make German Ale, I use the tri-decoction method. The process creates a finer Ale, when it is done right. The decoctions I pull are between 4 and 5 gallons. Way more than a couple of quarts. Your beer will be good.

 

[ScottG58]

Thanks for the reply. I did not do a step mash. I pulled a thick mash for the decoction as I had read most of the enzymes that convert are in the liquid portion of the mash.

I would love to have a direct fired system. Right now the orange cooler is what I can afford. Someday, there will be a HERMS in my garage.

 

[tootal]

Did you only pull mash liquid to boil? If you did, don't until after conversion, to reach mash out temp. If you pulled mostly mash for the decoction, did you do a protein rest in the decocted mash? Or a protein rest in the mash tun? If not, don't worrying about it. Protein rest temps are well below 147F. You should know that if you are doing decoctions. If you pulled mostly mash for the decoction, did you allow it to convert before boiling? If not, try it next time. Worry if the pH was out of whack when you boiled the mash. Munich and Vienna are high modified with just a little less diastatic power than pale or lager, due to the way the malt is kilned. Floor malts are lower modified. Malted and kilned at lower temps than high modified and are more suitable for decoction. When the topic that a protein rest isn't needed with high modified malt comes up, it is only one line taken from a 50 page text. There's more to it. British malt is modified to the point that a protein rest will thin the beer, drastically. The protein rest should be omitted. But, it would be very stable beer, if a protein rest was employed. Using Continental malt, it will take about 2 hours for a protein rest to overly thin the beer. There are branching and debranching enzymes being employed during the rest, even though the starch may not be completely gelatinized. There are other enzymes besides alpha and beta in malt, that improve the final product. Use them. There might be a little more to brewing beer than pouring hot water on grain and waiting for something to happen. Look into Weyermann's recipes. Many call for a protein rest using their high modified malt. If you are worried about keeping spot on conversion temps and you don't want to infuse hot water or pull a decoction, buy a mash tun that you can fire. Even if you used hot water to jack up the temp, a thin mash converts quicker. The very few times I make German Ale, I use the tri-decoction method. The process creates a finer Ale, when it is done right. The decoctions I pull are between 4 and 5 gallons. Way more than a couple of quarts. Your beer will be good.

Another part of the protein rest question is the temperature of the rest. If your using a simple under modified malt from Moravia then the proverbial 122 degree rest if great but most malts today are highly modified or nearly so. A 127 rest for semi modified pilsner malts and a 131 for the higher modified malts will help with efficiency as long as you don't go over 20 minutes or so. We did a 131 rest with Marris Otter for 20 minutes and the beer has great head retension and it's not thin. Our efficiency went up 2% too. Now we are set up for step mashing and if someone is not then it wouldn't be worth the effort.

 

[VladOfTrub]

Steve. Yes, enzymes are in the mash liquid in the tun. However, there are enzymes in the small amount of liquid in the decoction mash. If you pulled the decoction with it at 147F, raise the decoction temp to 155-158F and allow it to convert. Then take it to boiling. The main mash will be converting at 147F (beta) during the time it takes to bring the decoction through conversion and boiling. The decoction conversion will be in the alpha temp range and hopefully at a pH of at least 5.8, which alpha favors. The beer will have more character. Mash pH is important when it comes to boiling it. High pH strips tannin from the husk and into the final product. If the tun is too small, stepping with water is tough. My idea is, if I have to heat water to do a step mash. Why not just heat the mash? Getting the benefits from taking the diastatic enzymes through their optimum temperature and pH ranges a few times and from boiling it.


The SNR of most British Pale or Lager malt, depending on the malster, can be between 40 to 45%. Malt above 40 SNR is considered over modified. Malt, 40 SNR and above is suitable for infusion, not so suitable for step or decoction. Budvar is 25 to 33%, considered under modified. It is the best malt that I have ever used for Lager and Pils. It hasn't been available since the early 90's. Moravian malt, depending on the malster, can be 33 to 38%. Marris is the name given to the grain. The SNR depends on the malster that malts it. I think it is a lower modified floor malt. A protein rest would be OK with the malt if the SNR is 38 or below. Proteinase optimum temp is 122-140F, only, if the mash pH range is 4.7 to 5. If nothing is done to lower mash pH, less occurs with changing the protein chain. The rest creates albuminus proteins, responsible for body and head. Maybe, Phytin isn't kilned out of Marris and it helped lower the pH during the rest. If all the ducks lined up, the mash pH should drop lower than 5.4 pH during the 131F rest. I don't use Marris nor brew English ale. I wouldn't know what pH Marris would stick at, if Phytin is kilned out, or whether 20 minutes would do anything with regards to protein or pH. The malt by nature, might only lower pH between 5.5 and 5.8. The noticed increase in efficiency came from enzymes that are active during the rest temp, converting starch. There was more extract produced. The higher the protein rest temp is, the higher the final conversion temp should be.