Boil with Lid on or off

[A1sportsdad]

I’m guessing I should be doing my boil with the lid off based on the estimate of the amount of boil off. Is this correct? Is this the only reason?

Thanks

 

[stevehaun]

Yes boiling with the lid off allows for evaporation of dimethylsulfide (DMS).

 

[Bilsch]

Partially covering the kettle works best for me.

 

[Cato1507]

Yes, I boil with lid off. Always

 

[IslandLizard]

Your boil off is based on your boil process. Whichever you use, lid on, lid off, partially on, heat source, boil intensity, ambient conditions, etc.
Adjust your starting/sparging volumes accordingly.

And as @stevehaun said, to drive off DMS (and SMM).
Here's an interesting read on that:
http://scottjanish.com/how-to-prevent-dms-in-beer/

 

[soccerdad]

Depending on how strong your heat source is, you may need to partially cover the kettle, but let steam escape to boil away any uglies.

 

[A1sportsdad]

Your boil off is based on your boil process. Whichever you use, lid on, lid off, partially on, heat source, boil intensity, ambient conditions, etc.
Adjust your starting/sparging volumes accordingly.

And as @stevehaun said, to drive off DMS (and SMM).
Here's an interesting read on that:
http://scottjanish.com/how-to-prevent-dms-in-beer/

Great information. I had no idea about DMS. I’ll be curious to see how one of my beers tastes now boiling with the lid off. The article also seams to indicate that boiling harder is better as well. How hard do you boil your wort?

 

[Robert65]

Sorry, but that runs counter to everything known to modern brewing science and practice. It takes about 30 minutes at 100°C at pH 5.4 to convert SMM to DMS. This can be done with no "vigor" whatsoever and the lid on (notice there are no removable lids on commercial kettles.) Then just ten minutes of venting with sufficient wort circulation to bring every bit to exposure at the surface will expel the DMS. It should also be noted that modern malts, including Pilsner, contain very low to no SMM. Excessive thermal stress on the wort is extremly damaging, leading to effects like dull malt flavors, poor body and foam, rapid staling of the beer, and more. Best practice is a gentle simmer, providing constant but gentle circulation, covered as fully as possible, limiting total evaporation to 4-6% of initial volume.

 

[soccerdad]

I'm not a commercial brewer so I tend to follow generally accepted practice for home brewers. I have always considered venting the kettle for the full 60 to 90 boil to be generally accepted practice. I think any science says that water boils at 212/100, so I feel no need to go way above that in the boil. Also there is less oxygen ingress with a gentle boil v a vigorous boil. Again, that a generally accepted concept - I have not measured it beyond the beer tasting good.

 

[WBCo]

I boil with the lid on and a DIY steam slayer because I don't have any ventilation solutions in my basement where I brew. Works great and I can boil 7.5 gallons of wort with only 65% power with a 1650W element.

 

[Gulo_gulo]

It should also be noted that modern malts, including Pilsner, contain very low to no SMM.

Interesting. I didn't realize that modern malts were 'improved' in that way, and still thought DMS produced from SMM would 'drip back into the boil if the lid was on' according to 'conventional wisdom'. Good info!

 

[Robert65]

Most accepted homebrew practice is based on parroted misinformation and "all the kids are doing it."

Boiling with the lid on allows good circulation to be achieved with less heat applied (less thermal stress on the wort.) Another trick that can greatly assist this is asymmetrically heating the kettle -- flame off center. Partial venting, or removing the lid for a very short time at the end, is sufficient for driving off undesirable volatiles.

 

[odie]

I used to boil with the lid on for improved efficiency (uses less propane). and then when I went to a 110V water heater element the lid help achieve and maintain a vigorous boil.

Then I heard about all this DMS stuff so now I boil with the lid off...the result is more of a gentle boil/simmer...

yeah, I too sometimes fall into the "all the other kids are doing it" camp...

 

[Gulo_gulo]

Boiling with the lid on allows good circulation to be achieved with less heat applied (less thermal stress on the wort.)

Still need a good hot break for proteins though?

 

[Robert65]

Still need a good hot break for proteins though?

That's one reason you need to maintain circulation of the wort. It doesn't need to be extremely vigorous, gentle circulation will still effect good protein coagulation. Physical action of hops in that circulating wort helps also. Excessive boiling goes too far, degrading proteins leading to inferior body and foam qualities.

 

[A1sportsdad]

That's one reason you need to maintain circulation of the wort. It doesn't need to be extremely vigorous, gentle circulation will still effect good protein coagulation. Physical action of hops in that circulating wort helps also. Excessive boiling goes too far, degrading proteins leading to inferior body and foam qualities.

So sounds like just a good rolling boil is best.

[emoji1303]

 

[fendersrule]

I boil with lid off. I also boil at a moderate level. I always keep a nice bubble going from a boil. If it’s a huge pocket that’s splashing up on the sides of the kettle then I turn down the heat.

 

[MuddyBrown]

If you need to have the lid partially on to help with the boil, consider using a stainless steel bowl of some specific diameter instead. Fill with known volume of water every time, cover with foil and use this setup every time for consistency. The bowl reduces total surface area which decreases the effective heat loss and which in turn increases the overall boil intensity. Just have to choose a bowl that is not huge, or too small. Too big of a bowl will impact stirring. I have used this in the past with great success to increase my boil vigor in a previous setup.

 

[Cato1507]

I boil with lid off. I also boil at a moderate level. I always keep a nice bubble going from a boil. If it’s a huge pocket that’s splashing up on the sides of the kettle then I turn down the heat.

My method too, I guess just because that was what I read to do when I started brewing a few years ago.

 

[TurnipGreen]

Most accepted homebrew practice is based on parroted misinformation and "all the kids are doing it."

Don’t forget magic and witches. Many of us flat earth brewers are perfectly comfortable assuming if we hold our mash paddles just right, the witches will allow beer to be made from sweet wort.

Kidding. I’ve always boiled with the lid off ‘cause that’s how we do it but I’ve been thinking about how to be more efficient and save a bit of time. I'm gonna make the switch to lid on for the next brew day.

Old habits die hard though. Look at all the questions on this site about whether a secondary is needed.

 

[fendersrule]

One thing is for sure: Boiling with the lid on creates more a of mess and requires more cleaning of the kettle.

 

[Robert65]

One thing is for sure: Boiling with the lid on creates more a of mess and requires more cleaning of the kettle.

Never had a single boil over or excessive foaming. Just have to leave the lid cracked a tiny bit, and remember you need to turn the heat down a fair bit.

 

[fendersrule]

Me neither, but you're still going to get trub coated on the lid and high up on the walls of the kettle. Just something I've observed.

 

[Robert65]

Me neither, but you're still going to get trub coated on the lid and high up on the walls of the kettle. Just something I've observed.

Not me. But the amount of scum we have to deal with may be a product of mashing procedures. I do step mashes and employ low oxygen methods, which makes a difference. Still, the payoffs of a lower intensity boil in wort quality and efficiency are probably worth a little extra cleaning. IMO.

 

[Cato1507]

Never had a single boil over or excessive foaming. Just have to leave the lid cracked a tiny bit, and remember you need to turn the heat down a fair bit.

Something I may check into trying partially covered, but I wouldn't want to do it until after hot break. Risk of boil over isn't worth it to me.

I'm still refining my boil off rates in BS with a new kettle, so a partial covering after hot break will change the rate a bit but shouldn't be a big issue.

 

[stevehaun]

I could be wrong but I thought the half life for conversion of SMM to DMS was ~30 min at 100C and pH 5.40
If I am correct, half is converted at 30 min and 75% is converted at 1 hour. 75% conversion to DMS should be sufficient providing DMS has a route of escape (evaporation).

 

[stevehaun]

I could be wrong but I thought the half life for conversion of SMM to DMS was ~30 min at 100C and pH 5.40
If I am correct, half is converted at 30 min and 75% is converted at 1 hour. 75% conversion to DMS should be sufficient providing DMS has a route of escape (evaporation).

Boiling point of DMS is 37C.

 

[Robert65]

I could be wrong but I thought the half life for conversion of SMM to DMS was ~30 min at 100C and pH 5.40
If I am correct, half is converted at 30 min and 75% is converted at 1 hour. 75% conversion to DMS should be sufficient providing DMS has a route of escape (evaporation).

Yes, but as little as 2-3% total evaporation has been shown to be sufficient to expel it, provided sufficient circulation to expose all the wort at the surface at some point. So a minimally opened lid, or just a short time with the lid open, will do. Practically, taking into account other considerations, 4-6% evaporation over a 60 minute boil is a good target (and index of acceptable thermal loading.) Approaching 10%, detrimental effects outweigh benefits. And there is no reason to be venting the kettle and losing heat (requiring additional heat to be applied) until a significant amount of DMS is present to expel.

 

[stevehaun]

Yes, but as little as 2-3% total evaporation has been shown to be sufficient to expel it, provided sufficient circulation to expose all the wort at the surface at some point. So a minimally opened lid, or just a short time with the lid open, will do. Practically, taking into account other considerations, 4-6% evaporation over a 60 minute boil is a good target (and index of acceptable thermal loading.) Approaching 10%, detrimental effects outweigh benefits. And there is no reason to be venting the kettle and losing heat (requiring additional heat to be applied) until a significant amount of DMS is present to expel.

I think we are in agreement about the evaporation of DMS. I just thought your statement regarding conversion of SMM to DMS was not accurate.

 

[Robert65]

I think we are in agreement about the evaporation of DMS. I just thought your statement regarding conversion of SMM to DMS was not accurate.

Thanks for ensuring clarification.

 

[Robert65]

Another point to keep in mind in all this talk of DMS, is that it can later re-form in wort not quickly chilled to below 85°C/185°F, so brewers employing a whirlpool stand should rapidly chill to below this temperature before the extended stand, or they will just be chasing their tails in trying to eliminate DMS in the boil.

 

[RM-MN]

Another point to keep in mind in all this talk of DMS, is that it can later re-form in wort not quickly chilled to below 85°C/185°F, so brewers employing a whirlpool stand should rapidly chill to below this temperature before the extended stand, or they will just be chasing their tails in trying to eliminate DMS in the boil.

Some of these cautions on DMS don't add up. I BIAB, short mash time, half hour slow boil, no chill. All these in combination should give me nothing but creamed corn but I don't have any of that. I wonder why.

 

[Robert65]

My starting point always is, all these considerations apply IF troublesome levels of SMM are present in your malt. And that's not the case as often as conventional (outdated) wisdom would have us believe. So much of the received lore on wort boiling is misdirected.

 

[HopsNOps]

Wow, just reviewing this and thank you all for the questions and advice. What is the best indicator or test to confirm or know if there is too much DMS or SMM in our wort/beer?