Cover During Boiling?

[Cherry Bottom Brewing]

I am working on my second batch today, a Brewer's Best pale ale, and the directions do not say whether or not to use a lid on the brew pot during the boil. I am most of the way through the 60 minute boil, and I have noticed that quite a bit of the wort has boild away, maybe an inch or two in a 20 quart pot. Is this normal/supposed to happen?

 

[Buford]

If you keep the lid on, the DMS driven off during the boil will condense with the evaporated water on the inside of the lid and drip back into the wort. Also, a covered pot will very easily boil over if the pot is mostly full.

That said, I leave my lid covering about 2/3 of the pot during the boil to keep enough heat in the pot to keep it at a rolling boil (I boil 6 1/2 gallons on an electric stove), but this lets steam out. In this case it's a compromise, but I haven't noticed any DMS off-flavors from doing this.

You will have boil off, which you have to compensate for by either topping up after the boil or starting with a greater volume of diluted wort than your expected final volume. I get about one gallon boil-off over the course of an hour in my pot.

 

[Cherry Bottom Brewing]

Thanks for the quick reply. What exactly is DMS?

Next batch I'll try keeping the lid on 2/3 of the way. I started with 2 gal. of water, steeped grains for 20 min at 160 and then brought to a boil and added 2 cans of LME and boiled for 55 min with bittering hops and then 5 min with fininshing hops. I use a clip on candy thermomiter during the steeping and left it in for the boil, and noticed the drop in liquid level.

 

[Buford]

DMS = dimethyl sulfide. Tastes like cooked corn or cabbage.

 

[Orfy]

Add more water to allow for th boil off.

 

[the_bird]

DMS is actually not THAT huge a deal with extract brews - most was already driven off through the manufacturing process (as per some dude from Breiss on Basic Brewing Radio). Still, if you can, keep the lid off and keep water from dripping back in.

The other HUGE issue with having the cover on; while a watched pot may never boil, a COVERED pot will ALWAYS boilover.

 

[Sir Humpsalot]

The other HUGE issue with having the cover on; while a watched pot may never boil, a COVERED pot will ALWAYS boilover.

LOL




132465798

 

[Cherry Bottom Brewing]

I think I'll just leave the lid off. The directions did say to move the chilled wort to the primary and add water to make 5 gallons. Thanks for all of the good info.