What is a "mash cap"?

[Gustatorian]

Saw the in a blog post and in the 4 years I've been brewing, I've never heard the term...

 

[day_trippr]

I think that's a term most used by distillers - who consider the "mash" to extend all the way through fermentation (which totally makes sense).
A "cap" in that context is what beer brewers would call "krausen" during the fermentation phase, although in their context the "cap" can be loaded with grain fragments [edit] that often dries into a crust...

Cheers!

 

[MaltMaker]

A mash cap is literally a physical cover that sits or floats on top of the mash.

The intent is to retain heat and limit exposure to oxygen while mashing.

It is commonly made from silicone, stainless steel or foam board covered with stainless steel tape but some have simply used a plate or a pizza pan.

In a recirculated mash system (RIMS or HERMS) there may be holes drilled through the mash cap to allow for recirculation.

 

[Gustatorian]

A mash cap is literally a physical cover that sits or floats on top of the mash.

The intent is to retain heat and limit exposure to oxygen while mashing.

It is commonly made from silicone, stainless steel or foam board covered with stainless steel tape but some have simply used a plate or a pizza pan.

In a recirculated mash system (RIMS or HERMS) there may be holes drilled through the mash cap to allow for recirculation.

Interesting. This would be used in Low DO homebrewing, I assume?

 

[jtratcliff]

In a beer brewing context, "capping the mash" is sometimes done when partigyle brewing.

After draining off the 1st runnings for your big beer, you add more grain to your mash
to alter the character (or up the gravity) of your small beer.

 

[MaltMaker]

Most useful in low oxygen brewing, yes.

 

[MrBJones]

A mash cap is literally a physical cover that sits or floats on top of the mash.

The intent is to retain heat and limit exposure to oxygen while mashing.

Wouldn't such a floating cap be a good oxygen barrier for use with a bottling bucket?

 

[day_trippr]

 

[brewerJase]

View attachment 391623

Hahahhahhahaa. Perfect.

 

[MaltMaker]

Wouldn't such a floating cap be a good oxygen barrier for use with a bottling bucket?

An interesting thought. I don't know that it would make that much of a difference in a bottling bucket as there are no oxygen scavengers save the yeast. One would need to somehow measure the DO of the beer in the bottling bucket after a period of time - on two different beers being bottled, one with the cap and one without.