Boiling with the lid on?

Greetings all. I searched for this but didn't find so I made one.

I am a stovetop extract brewer. Almost two years now.

I'd like to hear other brewers thoughts on how the final product is impacted by boiling with the lid on.

I think I've always done it because it wil boil sooner and sustain boil with less energy input.

I'm wondering now if I am preventing the escape of undesirables.

By the way, I also recently started listening to The Jamil Show and Brew Strong. Two very good podcasts. I recommend them to everyone interested in beer.

Thanx in advance for your feedback.

Currently I have nothing in P,S,B,K

Keeping the lid on the kettle stops DMS from escaping. Keep the lid off & turn the heat up during the boil.

Len_Andov said:

Greetings all. I searched for this but didn't find so I made one.

I am a stovetop extract brewer. Almost two years now.

I'd like to hear other brewers thoughts on how the final product is impacted by boiling with the lid on.

I think I've always done it because it wil boil sooner and sustain boil with less energy input.

I'm wondering now if I am preventing the escape of undesirables.

By the way, I also recently started listening to The Jamil Show and Brew Strong. Two very good podcasts. I recommend them to everyone interested in beer.

Thanx in advance for your feedback.

Currently I have nothing in P,S,B,K

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Sometimes can cause you to boil over.

If you're doing extract only, no grains, it would be okay, as boiling is part of the process of turning wort into extract.

It's okay to leave the lid on to help come up to a boil, but I'd remove it after that. You don't need a super vigorous boil, as long as the surface turns over enough to keep the foam down and the hops churning you're good to go.

I've been stovetop brewing this way for three years, extract and all-grain, no DMS or other problems.

I've been doing it 5 years plus, & finally got a 3,600W induction stove. The old coil style electric was Ok with aftermarket elements. But not as quick as this higher-powered stove. With the old GE stove, it took a bit longer to come to a boil, but leaving the lid on just till foam started coming up was ok. No need to bother with the lid at all now, save for mashing. Definitely no lid when the foam starts coming up right before the boil.

If you have difficulties gettign to boil temp, you can try to isolate the outside of your kettle


using high temp bubble wrap is definately a better idea if you can source it.

DMS is formed in the mash and during the boil of malt-based wort. See this Beersmith article.

Extract:
When you brew extract, there is absolutely no concern for DMS, it has already been boiled off by the maltster during extract production. So you can keep the lid on as much as you want, there's never a DMS problem, or any need to boil off anything.

There's really no need to boil all your extract either. Add 1/3 at the beginning of the boil, the balance after flameout. The wort tastes fresher that way, there is less caramelization, less wort darkening, and your hop utilization is higher. All win-win.

Partial Mash or All Grain:
If you do partial mash (PM), say 30-50% of your fermentables from grain, the rest from extract, or brew all grain (AG), you may keep the lid on partially, say, half way to retain a good boil. But you still need to crank up the heat source so your boil is vigorous (rolling) and you evaporate enough to drive off the DMS. For a 5 gallon all grain batch it's recommended to boil off a gallon per hour at minimum. For partial mash it can be a bit less, down to 1/2 a gallon/hr.

When I boiled PM/AG on the electric ceramic stove top, I also had to keep the lid on half way to retain a rolling boil. Even when set at full power, the huge triple element still cycled off and on perpetually (you can hear it). I guess it is to protect the element or top from overheating and damage. I also packed 2 layers of big-bubble wrap around the kettle to reduce heat loss. That worked great, never had any DMS issues.

Heating Brewing Water:
Now when you're just heating up your brew or sparge water, by all means keep the lid on or ajar to speed up the process. But after the mash, lid needs to be off or at least partially.

In addition to affecting the removal of volatiles like DMS precursor, I would think the one other effect would be reduction of wort volume. With the lid off, as you boil you are removing pure water so your wort volume decreases while the gravity increases.

I would do it just to get the wort to a boil, then remove the lid to allow some of the undesirables to boil off. You will lose volume but it's not much in 60 min

just crack it 2 inches but leave it on most of the time. dms will escape with the steam

myelo said:

In addition to affecting the removal of volatiles like DMS precursor, I would think the one other effect would be reduction of wort volume. With the lid off, as you boil you are removing pure water so your wort volume decreases while the gravity increases.

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I use refrigerated distilled water to bring the primary up to 5gallons mark. Would the evaporation loss be offset?

Maybe I misunderstood higher gravity

And thanx everyone for the responses.

Yes, it would. The gravity would go down to somewhere around recipe OG.

IslandLizard said:

DMS is formed in the mash and during the boil of malt-based wort. See this Beersmith article.

Extract:
When you brew extract, there is absolutely no concern for DMS, it has already been boiled off by the maltster during extract production. So you can keep the lid on as much as you want, there's never a DMS problem, or any need to boil off anything.

There's really no need to boil all your extract either. Add 1/3 at the beginning of the boil, the balance after flameout. The wort tastes fresher that way, there is less caramelization, less wort darkening, and your hop utilization is higher. All win-win.

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A little off topic, but since you brought it up... I have wondered about splitting the extract up to help with the color of the finished wort. If your recipe calls for adding whatever the amount of hops at 60 min, is only adding 1/3 of the extract at 60 ok? I know that the extract has already been boiled and I have read other suggestions of only boiling for maybe 30 minutes, but i have always wondered if that is enough time for the hops to do their thing. Not ending with the correct color of beer drives me nuts, but I dont want to affect the flavor just to get the right color.

Again, I apologize that this is off topic...

kennya said:

A little off topic, but since you brought it up... I have wondered about splitting the extract up to help with the color of the finished wort. If your recipe calls for adding whatever the amount of hops at 60 min, is only adding 1/3 of the extract at 60 ok? I know that the extract has already been boiled and I have read other suggestions of only boiling for maybe 30 minutes, but i have always wondered if that is enough time for the hops to do their thing. Not ending with the correct color of beer drives me nuts, but I dont want to affect the flavor just to get the right color.

Again, I apologize that this is off topic...

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No need to apologize, it's quite on topic. We've seen way worse offenses.

As long as your hops get boiled for 30-60 minutes the alpha acids will get isomerized to give you bitterness.

Now when the boil gravity is being reduced to 33% (1/3 of DME) hop utilization goes up significantly, so you may need to look at a hop utilization table (like the one in How to Brew) or use your recipe builder to reduce the hop addition by enough to stay at the correct IBUs, or let it ride and have a more bitter beer. For some styles (IPAs) that may be advantageous.

If you were to boil only for 30 minutes instead of the recipe's 60 to keep a lighter wort color, save time, energy, etc. again, utilization will be affected, but reduced this time, so you may need to use a little more hops to compensate. Or live with a little less bitter beer.

It's always good practice to re-calculate/tweak a recipe with the actual AA% of the hops you're using. A hop with 20-30% less AA will produce 20-30% less IBUs and a significantly less bitter beer. These deviations are not unheard of, due to where they were grown, the prevailing weather, time of harvest and how they were stored (aging) until you added them to the kettle.

You can also boil your hops with water alone in a pressure cooker to get your alpha acids super fast. If you're using 100% extract, you theoretically wouldn't have to boil your wort at all.

https://www.homebrewtalk.com/15-minute-brew-process.html

Great info! Thanks to you both! I will experiment with this on my next brew day.

Rotule said:

If you have difficulties gettign to boil temp, you can try to isolate the outside of your kettle with a blanket or towel, since I do that I reduced the time it takes to get to boiling temp considerably.

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This sounds incredibly dangerous. DON'T DO IT!!!!!

Rotule said:

If you have difficulties gettign to boil temp, you can try to isolate the outside of your kettle with a blanket or towel, since I do that I reduced the time it takes to get to boiling temp considerably.

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kh54s10 said:

This sounds incredibly dangerous. DON'T DO IT!!!!!

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Agreed, with an open flame, yeah, that's tempting fate.
But for many electrical heating sources that method can be used safely. As long as the fabric doesn't touch the glowing hot heat source. Too low mounted Reflectix can melt and weld itself to a glass cooktop...

I love induction just for its coolness, literally. Now a metal dish or pan can get unbelievably hot on those, enough to set a towel on fire. So it can still create havoc if you're not careful. Don't even ask how I know that.

IslandLizard said:

Agreed, with an open flame, yeah, that's tempting fate.
But for many electrical heating sources that method can be used safely. As long as the fabric doesn't touch the glowing hot heat source. Too low mounted Reflectix can melt and weld itself to a glass cooktop...

I love induction just for its coolness, literally. Now a metal dish or pan can get unbelievably hot on those, enough to set a towel on fire. So it can still create havoc if you're not careful. Don't even ask how I know that.

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Almost anyone asking about keeping the lid on during a boil do not have electrical heating that would not post a big hazard by wrapping the pot in towels or blankets. They are almost always using an electric stove.....

So, without noting exceptions, it is an extremely bad idea....

kh54s10 said:

Almost anyone asking about keeping the lid on during a boil do not have electrical heating that would not post a big hazard by wrapping the pot in towels or blankets. They are almost always using an electric stove.....

So, without noting exceptions, it is an extremely bad idea....

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Alright, your concerns are warranted, it is indeed a very bad idea! We don't want anyone earning Darwin Awards here.

My 14" pot used to overhang the largest element (13") in the flat top stove by about 1/2". I used 2 layers of plastic bubble wrap and the lid on half way in an effort to keep more heat in. With care that could work, as it won't touch the glowing element, although the surroundings get really hot too. Aside from the weight on that glass top being roundout scary, it was still not boiling vigorously enough, hence I got an induction plate and never looked back.

kh54s10 said:

Almost anyone asking about keeping the lid on during a boil do not have electrical heating that would not post a big hazard by wrapping the pot in towels or blankets. They are almost always using an electric stove.....

So, without noting exceptions, it is an extremely bad idea....

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in my setup, my kettle is almost a 1.5 X diameter than my electric stovetop element, there is absolutely no risk of burning that blanket...

but yhea, one could use brain functions to identify potential danger in his particular setup.

using bubble wrap is better indeed .

Rotule said:

in my setup, my kettle is almost a 1.5 X diameter than my electric stovetop element, there is absolutely no risk of burning that blanket...

but yhea, one could use brain functions to identify potential danger in his particular setup.

using bubble wrap is better indeed .

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Famous last words. I hope you don't live in a multifamily building....... Your poor neighbors when the place burns down.