Lid on or off during boiling?

[Obadiah Boondoggle]

Hi All

I have a Klarstein Masher/Boiler

I always leave the lid on during boiling (It has vent holes to allow steam to escape)

I have been told today that you should not leave the lid on - that it is better to let the steam boil away (rather than drip back into the brew) and then if necessary top the wort up at the end with water

Lid on or off?

 

[uDicko]

I boil with lid off... Probably more down to "the way I've always done it"

 

[Cheshire Cat]

Off as you could/will get boil over.

 

[Drunkula]

If I was using pilsner malt then half way on, otherwise whatever gave me the boil off I was expecting.

 

[Clint]

Off.

 

[terrym]

Try this
https://www.thehomebrewforum.co.uk/threads/topless-or-top-on.88618/#post-929862

 

[The-Engineer-That-Brews]

Each to their own on this one I think, but my preference is lid ON.
It means I can dial back the heater power considerably (by about 40%) to maintain a good rolling boil, and also reduces the amount of water that boils off and ends us as condensation on my walls. There are still the steam vents to allow any volatiles to escape...
You do need power control though otherwise you’ll get boil over for sure!

 

[The-Engineer-That-Brews]

it is better to let the steam boil away (rather than drip back into the brew)

I’m very confident that after the initial 5-10 mins of boil, the only thing you’re going to get condensing on the lid and dripping back into the brew is good old 100% pure distilled H2O.
In any case, once the lid comes up to temperature you won’t get any condensation on it anyhow - you’re just vaporising water for no good reason.

 

[Obadiah Boondoggle]

I’m very confident that after the initial 5-10 mins of boil, the only thing you’re going to get condensing on the lid and dripping back into the brew is good old 100% pure distilled H2O.
In any case, once the lid comes up to temperature you won’t get any condensation on it anyhow - you’re just vaporising water for no good reason.

Would that mean that you would leave the lid off for the first 5 - 10 mins?

Thanks for your reply

 

[Clint]

So...taking the lid off could be a waste of time,energy and water..this could save energy,water etc...so a revised system requirements would be needed...this would be less to boiler,so less sparge or less mash...

 

[The-Engineer-That-Brews]

Would that mean that you would leave the lid off for the first 5 - 10 mins?

Yep, I do - although mostly so I can see when it’s fully come up to the boil, then lid on and dial back the heater power (NB: power, not thermostat!)

 

[Obadiah Boondoggle]

So...taking the lid off could be a waste of time,energy and water..this could save energy,water etc...so a revised system requirements would be needed...this would be less to boiler,so less sparge or less mash...

Yes

 

[foxbat]

Off. Always off. One of the reasons for boiling is to allow SMM to convert to DMS and be driven off. Granted, modern malting minimises SMM but why would you risk it?

 

[Obadiah Boondoggle]

Off. Always off. One of the reasons for boiling is to allow SMM to convert to DMS and be driven off. Granted, modern malting minimises SMM but why would you risk it?

SMM?

DMS?

 

[Richard_H]

I was under the impression that during the boil there are certain flavours/chemicals that need to escape via the steam produced, and that boiling with a lid on can impact the overall taste of your beer.

Perhaps this is more important for people like me who have a stainless steel lid with no ventilation?

 

[Banbeer]

I leave the lid off.

 

[strange-steve]

Off. Always off. One of the reasons for boiling is to allow SMM to convert to DMS and be driven off. Granted, modern malting minimises SMM but why would you risk it?

I agree with this but ie heard, as the engineer says, 15 mins or so is enough to remove those volatiles.
Another reason for lid off might be to achieve more evaporation for the purpose of concentration of the wort. This can be useful for improving efficiency with big beers.

 

[The-Engineer-That-Brews]

Whatever SMM and DMM are, it seems to me that there are two options here:

1. Their boiling point is less than that of water. In this case they vaporise quickly and either escape via the steam vents or condense on the lid and drip back into the brew - at which point they again vaporise rapidly, etc, until having escaped as steam.
2. Their boiling point is more than that of water. In this case they will not vaporise, and remain in the brew whether the lid is on or off.

 

[Clint]

I agree with this but ie heard, as the engineer says, 15 mins or so is enough to remove those volatiles.
Another reason for lid off might be to achieve more evaporation for the purpose of concentration of the wort. This can be useful for improving efficiency with big beers.

Yeah but if you was leaving the lid on you would have already compensated for the lack of boil off with reduced volume to kettle so you would be starting with a similar finished boil size..

 

[Benfleet Brewery]

Off. Always off. One of the reasons for boiling is to allow SMM to convert to DMS and be driven off. Granted, modern malting minimises SMM but why would you risk it?

I’ve always used a Peco and adjusted the lid between on, off, and halfway in between in order to maintain a decent rolling boil without it boiling over. So how would this work with, say, a Brewzilla. I’ve just bought one but not had a chance to use it yet. This has a decent sized hole in the centre of the lid. I wonder if that would be sufficient to let anything that needs to escape to do so but keep some heat and water in to reduce energy and water wastage.