boiling hops

[parky]

Hi All,
When i boil hops in my 19lt pot, should the lid be on or off.
Cheers
Popey

[Rookie]

Hi All,
When i boil hops in my 19lt pot, should the lid be on or off.
Cheers
Popey

Off.

[killer]

Or at least partially off... A portion of the surface should be uncovered, not necessarily all of it.

[parky]

Hi Rookie,
Could you tell me, why i should leave the lid off.
Regards
Parky
edit Thanks Killer, I must of been typing when you posted, same question to you,
Thank you.

[jimp2003]

Hi parky.

There are a few reasons to keep the lid off:

1. There will be a high risk of the brew boiling over if you have the lid on - cleaning burnt wort off your boiler or stove is real pain.
2. Most recipes rely on you losing an amount of the liquid through evaporation in order to concentrate the wort and reach the intended post-boil gravity
3. During the boil certain compounds that are supposed to cause unwanted flavours are evaporated off. If you kept the lid on these would remain in your beer.

Hope that helps.

Jim

[parky]

Hi Jimp2003,
Thank you for your answer, because i kept my lid on i lost very little to evaporation, and could not work out why i needed so much spurge water, now i know why i need to top up.
Thanks again
Parky

[orlando]

3. During the boil certain compounds that are supposed to cause unwanted flavours are evaporated off. If you kept the lid on these would remain in your beer.

DMS (Dimethyl Sulphide), one of the reasons for chilling the wort down quickly after the boil is that it can reform in the wort. Once in your brew it is an unpleasant aroma that doesn't mature out. Always boil without a lid or have good extraction if you do. I have seen some setups that do this to avoid steaming up the place.

You can probably tell from this brew day I don't have it