Boiling with top on

I just sampled my second extract batch, which was my first with adding my own hops, and it seemed to have an off taste similar to my first batch which was just a Coopers Real Ale kit recipe. This got me thinking I messed up somehow and after re-reading my books I came across a line saying it was best to boil with the lid off. I'm wondering if this was the problem so I wanted to know if anyone had done this and could confirm it can be enough a problem that it causes an off taste. I'd like to describe the taste but I really can't explain it well enough yet. I may have a friend taste it to see if they can help pin it down.

My third batch is almost ready for bottling and used the same boil method so I have to wait to start and finish my 4th batch to try and taste a difference.

DMS. dimethyl sulfide

Best described as a cream corn flavor.

Might be what you are tasting.

You definitely want to boil with the lid off.

My understanding is that DMS will not boil off if the lid is on during the boil. check out the Wiki. https://www.homebrewtalk.com/wiki/index.php/Dimethyl_sulfides#Causes_of_DMS[/URL]

I have never tasted what the article discribes but it says a cooked or creamed corn taste.

Isn't DMS a non-issue with extract?

Extract is already boiled?

Also, there is that little technique of late extract addition? If DMS were an issue with extract beers, then late extract additions wouldnt work would they?

The Pol said:

Extract is already boiled?

Also, there is that little technique of late extract addition? If DMS were an issue with extract beers, then late extract additions wouldnt work would they?

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Shhhhh! I've gotten in the habit of telling women they always have to boil wort topless. Don't start coming round with exceptions to the rule.

I boil with the lid on to reduce evaporation. Granted, I've only brewed three batches, but the second one yielded fewer than 30 bottles, because — I guess — so much of the liquid boiled off. No "creamed corn" taste here.

Sneaker said:

I boil with the lid on to reduce evaporation. Granted, I've only brewed three batches, but the second one yielded fewer than 30 bottles, because — I guess — so much of the liquid boiled off. No "creamed corn" taste here.

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Don't mean to hijack the thread, but I think you will get better results with the lid off.

As far as evaporation and only getting 30 brews goes...that's very odd. Are you doing extract? If so, top off after your boil to 5 gallons or even a little more. If you're AG figure out your evap rate and boil x gallons so that you'll have 5 to 5.5 done after the boil.

My 2nd and 3rd batch were actually with LME and hops (from recipes in my intro book) so both were boiled for around 60 minutes.

Dang. Sounds like I have to wait for the 4th batch to see if that's the problem. I'm also going to put the carboy into a cooler of water to see if that helps.

OK, I read the info on the wiki about DMS but frankly it got over my head. Someone mentioned earlier in the thread that DMS wasn't a factor in brewing with extract. Is that true?

I brewed my first batch (a nut brown ale) with the lid on because I brewed it on our electric glass top stove and needed the cover to get the temp up to boiling. I did notice an off taste though I don't think "creamed corn" would describe it. Anyway I am brewing on a propane cooker in a 26 qt. pot now and no lid is involved until cooling time (I assume lid on then is OK since I want to keep "stuff" out.

So is DMS an issue with extract?

This is a helpful link

The Brewing Network.com - :

Sounds to me like its the classic case of the water your are using has some chemicals or natural things in it, most tap water does. Are you using tap water? Some water has things in it, including my tap water which is the best tasting tap water I have ever come across, but if the lid is on or I don't boil for long enough I get goofy off tastes. Even if you think your water is really good it may have chemicals that need to be released by the boil, if the lid is on some of these might not escape.

One thing I don't understand is when people say they are putting the lid on the get the boil started. Are you then leaving it on? There is no issue to having the lid on to start a boil, but then it is up to 212 degrees and is not going to drop because you take the lid off, at that point the stove should easily keep it to temp. So just start the boil with the lid on then take it off to release any weird chemicals and do a full 60 minute boil to be as sure as possible that you have the purest h2o you can get from what you have.

Another thing you can do if necessary is to go to a store and buy some of those 2.5 gallon spring water jugs. In my area (which is very expensive) they cost me $3.50 or so for a 2.5 gallon jug of purified and filtered spring water. Do not get distilled water as it doesn't have some of the nutrients that the yeasties like, to my understanding. So just use a couple of those on brew day if you are still getting off flavors.