Conveting a Single Infusion Mash to a Hochkurz Double Decoction Mash

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DSmith

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Is converting a mash from single infusion to decoction simply trial & error?

I've experimented with the decoction step for mashout to get familiar with the process and now want to do a Hochkurz Double Decoction (145F maltose rest by infusion, 158F dextrinization rest by thick decoction, 168F mashout by thin decoction) for a Vienna lager. (I know another way is to mash in at the protein rest temperature and decoct to the single infusion rest temperature but I'd like to avoid the protein rest)

Is there any advice about the maltose rest starting temperature and time to equal fermentability from a 152F single infusion mash? I suspect that the mash will lose heat faster with the decoction removed and the time at the maltose step is dictated by the heating/resting/boiling of the decoction and could easily be 90 minutes.
 
It's trial and error. I'd start with pulling the decoction after 20 min.

I have to check my logs to see of I have done useful data points for you.

Kai
 
I checked my logs and you should go with a 30 min rest at 63 C before pulling the first decoction. I generally get around 80% attenuation limit that way. In my case the decoction takes about 20 min to come to a boil and then I boil for 10 - 30 min.

It also depends on the malt, but I assume you are using lots of Pilsner and Munich or Vienna malt. But it will be something you can change for future batches.

Kai
 
I think 30 min at 63 C is a good start. the 72 C rest can be held until conversion is complete or for 45-60 min. The literature mentions foam and mouthfeel benefits for a long rest at this temperature.

Kai
 
Thanks again for looking up your mash schedule for the Vienna lager. I studied your website and watched the youtube videos again and have decided the enhanced double decoction shown in your video is the one to try because so many recipes are written for a single saccrification rest temperature. The fermentability probably won't be exactly the same as a single infusion mash but decocting up to that rest temperature is a good first guess.
 
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