Rolling boil - lid on or off?

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normanh

Re: Rolling boil - lid on or off?

Post by normanh » Mon Feb 23, 2015 10:28 pm

If ever you have smelt DMS you will know it its such a pungent sulphurous rubber odour you cant mistake it. You wont forget it in a hurry, I would be very suprised if any appreciable quanitities are found but then it only takes a little. Similar compunds are used to odourise natural gas so that gives you a benchmark and in that case the quantities added are from memory less than parts per million.

Norman

brewnaboinne

Re: Rolling boil - lid on or off?

Post by brewnaboinne » Wed Feb 25, 2015 11:11 am

Some kind of exhaust pipe sounds like good idea. Did a brew yesterday ,cold weather, steam condensing everywhere pita so put lid on = boil over even more pita. If I brew directly under the extractor hood some condensate drips back , is this likely to contain DMS or would this be just like distilled water?

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Kev888
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Re: Rolling boil - lid on or off?

Post by Kev888 » Wed Feb 25, 2015 12:55 pm

Theres very unlikely IMO to be much in the way of DMS condensing in a very open setup like a hood; it'll mostly be up and away. Even the amount of less volatile water vapour condensing would be a tiny portion of that being driven off.

If it were instead a long chimney/vent then for me it would have a bend in it to lead slightly downwards, in order to make condensation run away rather than back to the boiler. The only stuff dripping back would then be from the initial steam-heated portion of the vent which would (a) be too hot to condense DMS and (b) hot enough to kill most nasties. it would also need to be big enough diameter to prevent boil overs (especially if you have no power control). The lid fully on without a vent is useful when bringing to the boil, but I wouldn't leave it like that once the boil begins, I always crack it open at least an inch or more.

If your hood is high enough not to get very hot, drips returning may not be sanitised - no problem during the boil, but you may want to put some sort of cover over the boiler once its cooling down. Perceived wisdom would say loosely at first so as not to trap any remaining DMS/DMSO vapour should there be any, however the no-chill crowd don't seem to suffer and they completely seal their hot wort, so perhaps its no biggie. I cover mine at that stage with no issues, partly to keep flies out and partly because the drips are from a less-than-sanitary garage ceiling.

Cheers
Kev
Kev

daf

Re: Rolling boil - lid on or off?

Post by daf » Wed Feb 25, 2015 2:15 pm

normanh wrote:If ever you have smelt DMS you will know it its such a pungent sulphurous rubber odour you cant mistake it. You wont forget it in a hurry, I would be very suprised if any appreciable quanitities are found but then it only takes a little. Similar compunds are used to odourise natural gas so that gives you a benchmark and in that case the quantities added are from memory less than parts per million.

Norman
Smells like this then?

:mrgreen:

Image

brewnaboinne

Re: Rolling boil - lid on or off?

Post by brewnaboinne » Wed Feb 25, 2015 2:41 pm

Thanks Kev, I'm thinking a curtain all the way round the cooker hood and something to hold the lid securely part open would do the job
Cheers

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Kev888
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Re: Rolling boil - lid on or off?

Post by Kev888 » Wed Feb 25, 2015 5:51 pm

Interesting idea; sounds better than mine. I tend to just ledge the lid about an inch or so to one side of being centred on the pot, its easy to adjust how much it covers then but it does drip condensation from the overhanging edge onto the floor and I have to put it fully on again after the boil (as I've no other way of keeping flies out).

Cheers
Kev
Kev

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