Decoction mash on Dunkel?

Never done a Decoction mash. Wondering if a single decoction mash for a Bavarian Dunkel at 122 and 153 with 170 mash out would truly make a difference. Or just do a single at 153 or so.

Regardless of which method you choose 153F is too high for the main rest IMO. Most German lagers will benefit from a low temp main rest ~148F to obtain a clean, slightly dry finish. If you choose decoction I would suggest 128F/148F/168F.

The merits of a decoction mash are the subject of debate. I say if you want to do one, it is certainly an appropriate method for a dunkel. Personally I think 153F might be about right for the sacch rest if you aren’t doing both a beta (145F) and alpha (158F). A dunkel is supposed to have a certain amount of sweetness and body, and if you aren’t adding this with caramunich then the higher mash temp will substitute. I don’t know that you’d need the protein rest although that is another topic of debate and it is certainly dependent on the type of malt used.

Decoctions are a little messy until you get a system worked out. You’ll find you get a little boost in efficiency from the method, and the color will be a little darker than if you did a single infusion. Take those things into account in formulating your recipe.

I have serious doubts about the benefits of decoction based on my experience and some experiments I’ve done. That said, if it sounds like something you want to do, go for it. I’d advise you skip the rest at 122 and just do beta and alpha rests…maybe 146 and 162.