[rungdalek]

Is DME subject to oxidation?

Is it nitrogen flushed and packaged by any of the manufacturers Briess/Muntons?

[majorvices]

This is a good question and I think someone will come along with a smarter answer than what I am going to give - but I would say that whatever affect oxidation has on DME it is far less of an affect than it does on LME due to the nature of its processing.

[rungdalek]

My take is that since it's hygroscopic it will absorb moisture from the air which presumably contains oxygen, unless of course it's kept in an environment where that doesn't have to be considered but I'm not a scientist.

[majorvices]

My take is that since it's hygroscopic it will absorb moisture from the air which presumably contains oxygen, unless of course it's kept in an environment where that doesn't have to be considered but I'm not a scientist.

I think you are definitely correct. But if kept dry it most likely isn't subjected to any more oxidation than crushed malt - which does have a shelf life but if kept sealed is pretty long.

[kramerog]

DME is probably more shelf stable than malt because there are no active enzymes.

[rungdalek]

Not being a scientist I could be wrong but the enzymes in malt aren't active either until they're activated by environmental conditions (water at a certain temperature).  Malt stales because it contains and absorbs moisture leading to oxidation.  It also contains bacteria and fungi which may contribute to fouling.

[denny]

Not being a scientist I could be wrong but the enzymes in malt aren't active either until they're activated by environmental conditions (water at a certain temperature).  Malt stales because it contains and absorbs moisture leading to oxidation.  It also contains bacteria and fungi which may contribute to fouling.

DME is dried wort that has already been boiled. That means is has no enzymes.

[jeffy]

I occasionally purchase a bag of DME for starters and keep it sealed in a plastic bag in a drawer in the kitchen.  After a month or more it turns into a brick from moisture absorption, but it's still good for starters.  If I leave it a lot longer it will darken from oxygen pick up.  At this point it doesn't make a very good starter.

[rungdalek]

Not being a scientist I could be wrong but the enzymes in malt aren't active either until they're activated by environmental conditions (water at a certain temperature).  Malt stales because it contains and absorbs moisture leading to oxidation.  It also contains bacteria and fungi which may contribute to fouling.

DME is dried wort that has already been boiled. That means is has no enzymes.

True, but I've never claimed that DME has enzymes.

[rungdalek]

I occasionally purchase a bag of DME for starters and keep it sealed in a plastic bag in a drawer in the kitchen.  After a month or more it turns into a brick from moisture absorption, but it's still good for starters.  If I leave it a lot longer it will darken from oxygen pick up.  At this point it doesn't make a very good starter.

This has been my experience as well.