Boil with or without lid?

[Mountainbeers]

So I've used my turkey fryer a few times now but one thing I never covered was whether or not I should boil with the lid on or off?

I've noticed most of you guys leave your lids off. Is there a reason for this? I get A LOT more evaporation when I leave my lid off.

If I leave the lid off for a 60 min boil, how much wort should I start with if I want to end up with 5.5 gal?

 

[nealf]

You will want to boil with the lid off. In short, it can cause off flavors to your beer if you do not let some chemicals boil out of the beer. Look up Dimethyl Sulfides (DMS):

http://www.howtobrew.com/section4/chapter21-2.html

I generally start with around 7 gallons of wort for a 5.5G batch, YMMV. Preboil volumes usually vary, 7G is a good starting point though.

 

[doobliebop]

Uncovered. If you boil covered, the DMS precursors won't be carried off. A generally accepted rule is about 5 to 10% per hour loss.


/doh nealf beat me to it. Take a look here for references...
http://www.brew365.com/technique_calculating_mash_water_volume.php

 

[Bassman]

I believe that there is nothing wrong with starting the heating processed to get that going quicker but once the wort is boiling then you should uncover it. However, you may want to be careful about boilovers if you are not watching it.

 

[Grinder12000]

I'll lose about a gallon on a typical 6 gallon boil. Evaporation is OK and not to be afraid of - just add cool water when you are done chilling, it'll drop the temp and you should have no problems.

 

[mmb]

I'm about 1.5G during a 60 minute boil. As everyone else says, you need to either boil with the lid off or get some way of catching the condensate so that it doesn't drip back into the wort.

 

[Arkador]

I leave the lid on while it is heating up, to hold in the temprature, but you want that thing uncovered for the entire boil.

 

[JayInJersey]

Here's a question for you spring/summer/fall outdoor brewers (IE on a patio/porch/roof)...

In my neck of the woods there are tons of flying beasties at any given time...birds, gnats, horseflies, and my personal fav falling leaves

Do any of you use a screen to protect the brew?

If the screen was fine enough (like a house window screen) to block the little critters, how do you handle condensation drip back?

 

[mychalg9]

The top of my brewpot is only a couple of inches below my over hood. Will the heat and/or steam ruin the hood over time?

 

[mychalg9]

EDIT:I meant to say microwave, not oven hood.

 

[JayInJersey]

Personally I have no concrete evidence...but I'd say yes, but probably no faster than using the stove would eventually ruin the bottom of the microwave.

I'm also assuming that if the microwave was made to be above the stove...the manufacturer though about making it so moisture couldn't seep in from the bottom, or added a built in oven vent to the bottom (I think that's how it is setup at my MIL's house)

 

[steelerguy]

I would imagine you are doing extract recipes otherwise you would need some evaporation after sparging or be willing to put up with pretty bad efficiencies (or I suppose making beers will really low OG).

If you are using LME or DME you don't have to worry as much about DMS since most of the precursors are driven off during the production of the extract. Lots of people at extract late and their beer turns out fine. You could keep the beer covered for most of the boil if you don't fear boil overs...I myself fear them a lot, they happen easy and fast when you have the pot covered...and you can't see it happening until it is too late. I would still let it boil uncovered the last 10-15 mins just to be safe.