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.