Decoction mash question

[nufad]

I'm planning my first decoction mash for a saison. I've read that the grist pulled from the mash should undergo a short (~ 10 min) saccharification step before boiling. It isn't clear to me why this should be the case - can someone explain why? Thanks!

 

[Gnomebrewer]

When you boil (actually, when you get over about 73 celsius) you destroy the enzymes that are able to convert starch to sugar. If you are only boiling a small amount AND if you have an enzyme rich mash (high diastatic power) you will get away without the rest as the enzymes in the non-decocted part of the mash will be capable of converting all of the starches. I often have large amounts of munich malt that only just have enough enzymes to convert it's own starch anyway, and decoct nearly half the mash, so I wouldn't get conversion if I didn't have a sacch rest before I boiled. I normally do a 20 minute rest at 68-70 Celsius before boiling.

 

[mjohnson]

You decoct a decent portion of the mash. So on your first decoction, you want to convert the disolved starches prior to boiling. As Gnome states, it probably makes it easier to ensure full conversion of the entire mash.

Additionally (I don't know if there is science to back this up), it seems to me some of the potential flavor enhancements of decoction mashes might be due to the long cooking time of the sugars. Conceptually, boiling starches doesn't seem like it would taste as good as boiling sugars. But, there are those that dispute the taste benefits of decoction. Apply as many grains of salt as you think are appropriate.