Lid on or off during boil?

[monkeypimp]

I was curious if everyone here left their lid on or off their pot during the boil.  I have a friend who leaves his off and I leave mine on…just curious if it makes any type of difference.

[stevo155 (theDarkSide)]

I leave mine off during the boil to drive off some of those compounds from the malt that could lead to DMS in the beer.  It was the way I learned when I started and don’t want to chance losing a batch to find out if it’s true or not.

Also, I use an immersion chiller and a hop spider so getting a lid to stay on there is a pain anyways.  I only put it on when I’m chilling to keep stuff from falling in. (Finally trained to wife not to turn on the dryer when I’m brewing…the vent is right by my brewing area).

[jrdunne (Joe Sr.)]

Off.  Always.  For the DMS reasons stated above.

If boil-off is too great, you can split the difference and leave it partially on.

[morticaixavier]

Off.  Always.  For the DMS reasons stated above.

If boil-off is too great, you can split the difference and leave it partially on.

or turn the fire down.

Lid off, mostly for avoidance of DMS, partially because I don’t have a lid for my kettle.

I cover with foil while chilling.

I have been thinking about covering while coming up to a boil to speed things up a little.

[klickitat_jim]

Off unless it’s so cold out my boil doesn’t seem full roll, then I rest it on my hop spider. Still full vent of vapors but a little shield from the cold.

[redbeerman]

OFF.

[monkeypimp]

Glad I asked!  The lid will remain off from now on!

[erockrph]

If I’m having a hard time getting as vigorous of a boil as I’d like, then I leave the lid on, but cracked about 1/3 of the way open. This lets DMS boil off, but still helps me keep a good boil going. I’ve never had a DMS problem, even in beers using a high percentage of Pils malt.

[denny]

Partially covered is fine.  Think of how many breweries have enclosed kettles.  But a study done many years ago concluded that you want at least 15% of your kettle surface uncovered.

[hopfenundmalz]

For monkeypimp- DMS tastes similar to creamed corn. Rolling Rock has that flavor defect. If you never picked it up in your beer, or Rolling Rock, you my have a very high sensitivity, or be flavor blind to it (some people are).

[mtnrockhopper (Jimmy K)]

@denny

Partially covered is fine.  Think of how many breweries have enclosed kettles.  But a study done many years ago concluded that you want at least 15% of your kettle surface uncovered.

Breweries have enclosed kettles, but they have stacks and probably exhaust fans too But still I’m sure partially covered is fine. The important point is letting steam escape before it condenses and returns to the wort.

[yso191]

I agree with all of the above.  However it is unimportant if you are brewing with Extract.  It really only applies to all-grain brewing since the DMS is gone out of extract.

[morticaixavier]

@yso191

I agree with all of the above.  However it is unimportant if you are brewing with Extract.  It really only applies to all-grain brewing since the DMS is gone out of extract.

don’t the precursors begin to reform once you get the wort above the magic temp? or is that another myth?

[skatz (Stevie)]

@mtnrockhopper

@denny

Partially covered is fine.  Think of how many breweries have enclosed kettles.  But a study done many years ago concluded that you want at least 15% of your kettle surface uncovered.

Breweries have enclosed kettles, but they have stacks and probably exhaust fans too But still I’m sure partially covered is fine. The important point is letting steam escape before it condenses and returns to the wort.

I think the exhaust stacks also have a lip on the inside to catch and divert any condensation out of the kettle.

[yso191]

@morticaixavier

@yso191

I agree with all of the above.  However it is unimportant if you are brewing with Extract.  It really only applies to all-grain brewing since the DMS is gone out of extract.

don’t the precursors begin to reform once you get the wort above the magic temp? or is that another myth?

Morticai, You are seriously beyond my experience level, but my understanding is that the precursor to DMS, which is SMM is entirely converted in a 90 minute boil.  I’m sure that the process of getting DME or LME goes way beyond what it takes to convert all the SMM to DMS and then blow that off.  However, I always take the safe route and defer to those more advanced than I.

[jrdunne (Joe Sr.)]

I always take the safe route and keep the lid off.

[monkeypimp]

I only in the last year made the move from the stove with a 4 gallon pot to the garage with a 15 gallon pot and never noticed any off taste before since I always brewed with the lid off.  I do partial mash…and usually do IPA’s  which i have never noticed any off tastes.  But recently have made a couple of pale ale and they have all had an off flavor that i can’t put my finger on.  It almost has a “burnt” type flavor…

I do usually leave my lid cracked or the pot tends to want to boil over…but condensation does from and drips back in…looks like my methods have changed!

[morticaixavier]

@yso191

@morticaixavier

@yso191

I agree with all of the above.  However it is unimportant if you are brewing with Extract.  It really only applies to all-grain brewing since the DMS is gone out of extract.

don’t the precursors begin to reform once you get the wort above the magic temp? or is that another myth?

Morticai, You are seriously beyond my experience level, but my understanding is that the precursor to DMS, which is SMM is entirely converted in a 90 minute boil.  I’m sure that the process of getting DME or LME goes way beyond what it takes to convert all the SMM to DMS and then blow that off.  However, I always take the safe route and defer to those more advanced than I.

I am pretty sure that anything I know about this is heresay from this forum.

In fact, here is a discussion about this very thing.

http://www.homebrewersassociation.org/forum/index.php?topic=33.0

@monkeypimp

I only in the last year made the move from the stove with a 4 gallon pot to the garage with a 15 gallon pot and never noticed any off taste before since I always brewed with the lid off.  I do partial mash…and usually do IPA’s  which i have never noticed any off tastes.  But recently have made a couple of pale ale and they have all had an off flavor that i can’t put my finger on.  It almost has a “burnt” type flavor…

I do usually leave my lid cracked or the pot tends to want to boil over…but condensation does from and drips back in…looks like my methods have changed!

What is your batch size?  I boil 40 liter batches (~49 liter preboil for a 90 minute boil) in a 50 liter pot and manage to avoid the worst of the boil overs with flame control. You really only need to see the wort turning over, it doesn’t have to be leaping out of the pot.

[monkeypimp]

I make both 5 gallon and 10 gallon batches…with the lid on and me not paying attention a 5 gallon batch will boil over…been done more than once!

[morticaixavier]

@monkeypimp

I make both 5 gallon and 10 gallon batches…with the lid on and me not paying attention a 5 gallon batch will boil over…been done more than once!

Oh yeah, with the lid on I can imagine. the only time I have had a boil over on a 5 gallon batch was when there was a lot of wheat in the grist… and I wasn’t paying attention.