Multi-Rest Infusion Beginner

[haileysmith]

Attempting a decoction infusion for the first time with my all-grain batch and having trouble finding much information about the process.
-how long should I expect this to take on average?
-is only the removed portion of water heated each time to raise the temperature of the mash? Or do I just remove a portion to be heated to raise the mash temperature for one of the rests and then directly heat the mash for remaining rests?

Any insights/ breakdown of steps would be really helpful!

 

[NordeastBrewer77]

This is where software really comes in handy. Are you infusing (with hot liquor/water) or decocting (boiling some of the mash and returning it to the mash to raise temps) or heating the mash to raise temps Or a combo of these? Again, brewing software will walk you through these steps, based on your recipe. That said, I can try to give you some pointers if you could share the recipe and mashing process.

 

[JimRausch]

J.P.'s book has a section on decoctions, but in this things seemed a little confusing.
Check out 'Braukaiser's' site. You will find everything you need about the theory and practice of decoction mashes. Plus it's good reading.
The simple answer is: you plug the temp you want to get to plus the temp you are currently at, plus total volume of your mash into the formula, and it tells you how much grain slurry to remove. You heat this up to your next rest temp., and leave it there for 10-15 minutes to convert that sample, then you boil it for 10-30 min. before adding it back to the main mash. Depending on how many rests you want to make, the whole process can take a while. But, IMO it's kind of fun. Good luck.

 

[JimRausch]

Sorry- the formula is:
Decoction volume= Total mash volume *( target temp.-starting temp)/ (boil temp-start temp.)