Originally Posted by meltroha
Is it possible to heat the vorlauf to the temperature of mash out infusion instead of adding water and changing the concentration on the mash? You would have to vorlaugh the proper amount to raise the mash up, would this be an easy decoction mash method? I just brewed my first all grain batch, and only achived 64%, so I'm looking for anything that might help.
Yes, draining some first runnings, boiling for a short time & returning to the mash tun is a "thin" decoction step. It's useful in high gravity brewing to maximize sparge water if you want to raise the mash temperature. It should only be done after conversion is complete because boiling wort will denature the enzymes. A "thick" decoction boils a minimal amount of wort plus more grain to leave more enzymes in the mash tun. You can also do this to get to mashout but I recommend checking for conversion because boiling the grain may give more starches to convert. They will convert very fast (10 min) if you raise the mash into the 160's. An iodine test is quick and very useful here.
You need to still vorlauf as usual.