No, this isn’t a story about a medieval torture device or a youtube video about a painful experience, but rather an effort to provide some relevant brewing content.
Since so many all-grain brewers use the ubiquitous blue or orange coolers as mash tuns, I thought this might be of interest. This is a German decoction-mash technique that works well for those mashing and batch sparging in a cooler or using some other non-direct fired mash tun. Of course, direct-fired mash tuns, like keggles, can use this technique too. You’ll achieve the same results as the famed double-decoction mash that is popular with German styles but without the guesswork about how much grain to remove for boiling or the complicated rests. Here we go.
Begin by heating mash strike water to the temperature necessary to achieve a step temperature of 127 degrees (protein rest) (Einmaischen 127F) at a water to grain ratio of 1.15qt/lb. As a practical matter, you would need to heat this water in your brew kettle and then transfer it to your cooler if you ordinarily use that as your mash tun. You would then add your grain bill to your kettle/keggle, not your cooler. Your kettle/keggle is serving as your mash tun for the protein and first saccharification rest. Add your strike water and keep an eye on the temp. You can add little heat if necessary with your burner if the temp drops, but 120dF to 130dF is adequate for a protein rest.
Rest 40 minutes
1st Saccharification Rest
– heat separately and infuse enough additional mash strike water to raise the water to grain ratio to 1.4qt/lb and heat to achieve a step temperature of 149dF
– rest 15min
– drain the thin, liquid portion (dunnmaisch) into your regular mash tun (cooler, keggle or brew kettle) until the remaining mash resembles moderately loose oatmeal or as the Germans say, dickmaisch!
– keep the thin liquid portion(dunnmaisch) at 149F or as close as possible. Obviously, the cooler mash tuns do a good job of maintaining temps so this shouldn’t be a problem.
– boil the entire remaining grain (dickmaisch) for 30min. You won’t be stopping for any rests in between but heat slowly to move the grain bill to a boil. Stir frequently prevent scorching.
2nd Saccharification Rest
– infuse to ~162F by combining the thick boiled grain and the thin liquid portion (dickmaisch and dunnmaisch) back into your regular mash tun.
– rest 45min
– if you intend on doing a mashout via lauter decoction* continue to the next step after 35 minutes have elapsed
Heat entire mash to 168 through direct heat if you have a direct fired system or begin a lauter decoction after 35 minutes into the 2nd Saccharification Rest.
*- Lauter decoction
– pull about 1/3 of the liquid (dunnmaisch) about 35min into the 2nd Saccharifcation Rest
– boil it until it breaks ~9-12min
– add back to mash to bring to mashout temperature (168-172).
BTW- A lauter decoction or mashout decoction is a good way to reach mashout temps and it’s also a good way to bring strike water up to a rest temperature should you miss you initial mash target.
Finally, lauter/sparge as you would with any other batch. The merits of decoction mashing are debatable but this technique really doesn’t require that much more effort and if it makes your German beers more authentic, then it may be worth the extra attention.