Decoction Question

[Cpsurfer]

I'm a pretty new AG brewer and haven't attempted any decoctions yet, but it's my understanding that (and I know I'm oversimplifying) a portion of the mash is taken out, boiled, and then returned to the main mash as an infusion.

When you take some of the mash for the decoction, do you scoop a bunch of "stuff" out of the tun or do you draw liquid out like you would at the sparge and just boil the fluid without any grains? Nothing I've read has really been clear on this for me.

I've been under the impression that boiling grains can release tanins and contribute to off flavors so I'd though the latter was true, but now I've also seen references to actually boiling some of the grist. Can anybody clear this up for me?

Thanks!

 

[Denny]

You boil the grains with as little liquid as possible. The enzymes from the grain are dissolved in the liquid and you don't want to denature them. When I do decoctions, I use a strainer to pull the grain. The reason you don't get tannins is because tannin extraction is very pH dependent and the pH of the grain in a decoction is too low to cause it to happen.

That said, experiments I've done lead me to believe that a single decoction will have little effect on the flavor of your beer, but I still encourage you to try it for yourself if you have a mind to.

 

[Cpsurfer]

Thanks Denny! And thanks for clearing up the tannin issue for me, that makes a lot of sense.