Late Extract Additions and DMS?

It seems pretty standard advice around here to add ~half your extract close to the end of the boil to minimize maillard reactions and darkening. How does this affect the chemicals in extract that are responsible for DMS? I've read in a few places that you want to boil your wort for 60 min with the lid off to rid your wort of DMS.

If you add half the extract at the end, couldn't you end up with Cream Corn Ale?

Nope. not in the least,as extract has already been through that while being produced to start with. The DMS boil off mainly referrs to partial mash & AG brewing where you mash your own grains to make the wort. then you leave the lid off to steam away DMS.

Interesting. Would it be okay to keep the lid on for a full extract batch then? My stove can't boil as much as I'd like, but it definitely does a better job with the lid on the pot.

I left the lid cracked a lil bit at the point where my electric stove's burners were startin to get weak. I then bought aftermarket burners on amazon,& can now get 3.5 gallons boiling in about 18 minutes on "8.5" with no lid. I put the link for'em in My Profile.

briannauta said:

Interesting. Would it be okay to keep the lid on for a full extract batch then? My stove can't boil as much as I'd like, but it definitely does a better job with the lid on the pot.

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I always thought that it was imperative to allow certain compounds from the hops to escape during the boil so you didn't get DMS type vegetal smells/flavours in the beer.

I leave the lid on whilst heating up for the boil and after adding DME, or some LME, but once I've made the first hop addition the lid is off until after flame out and some cooling down has been achieved.

The DMS comes from the grain not the hops. Extract has been boiled under a vacuum to help concentrate it. All chemical reactions necessary for good beer and healthy yeast have taken place already. The only reason to boil it is to sterilize it (technically it should be sterile already) and for hop isomerization. Boiling with lid on or off prob won't make much difference as most or all DMS should have been driven off already. Honestly the best beers with extract I have made were partial mash beers. The wort from the partial mash was boiled with hops then added to the extract in the fermenter. Top it off with distilled water and your good to go.

Yeah,DMS is completely grain related. Extract has already been through all that,so unless you use steeped grains or partial mash,as I do,you don't need to worry about partialy covering it.
And once again,you don't need to boil it to sanitize it. Pasteurization happens in seconds @ 162F. So a short steep after flame out extract additions is just fine. I do it all the time.
When I do my partial mash beers,the fresh grain wort is some 50% of the fermentables. I do all hop additions with that,adding all the extract at flame out.

The guy at my LHBS splits the extract as well just to prevent burn and giving the beer an overly astringent taste. But he said what everyone else has echoed that you won't run the risk of DMS.

No,not much risk of DMS with extracts. But it's not astringency you avoid with late additions,it's mailard reactions & that twang.

If you're doing a late extract addition (say 10 minutes left) how long do you need to let it boil before you can add your wort chiller?

I just got mine (chiller) and I've been told to put it into the boil for a 10-15 minutes or so to sterilize it. Sounds like a good idea but I wouldn't want all my extract clinging onto it. Nor do I want to put it in with 25 minutes left.

Or should I just spray the chiller with sanitizer then put it in the wort at flameout?

Thanks

Some soak the chiller in a bucket of starsan for a few minutes before putting it in the BK.

unionrdr said:

I left the lid cracked a lil bit at the point where my electric stove's burners were startin to get weak. I then bought aftermarket burners on amazon,& can now get 3.5 gallons boiling in about 18 minutes on "8.5" with no lid. I put the link for'em in My Profile.

Click to expand...

Wow that is crazy. It takes me 45 minutes to boil 3.5 gallons on my electric range with a lid.

http://byo.com/stories/issue/item/1101-making-malt-extract
This site is a good reference. What follows is copied/pasted from their site.

Carmelization and Volitization:
Brewing- grade extract has already undergone a kettle boil and extensive volatilization. Beneficial colors and flavors have been developed from carmelization and Maillard reactions in the kettle boil. Any volatile off aroma or flavors from the grain or DMS precursors have been removed. If the extract is diluted to wort and held at boiling temperatures without proper additional volatilization, additional precursors can be generated. In general, worts from malt extract do not need to be boiled to remove DMS precursors. However, if they are boiled, the boil must be vigorous enough to remove these precursors as more are created when wort is held hot.

^^All the more reason for late extract additions I do at flame out. Avoids having to boil them off from using LME in the boil,which is more redilly suseptable to these reactions. DME is less suseptable in my experiences. Good info flars.