Covering the Wort

[Mainer]

So, I know putting a lid on your kettle is a big no-no. My understanding is that this is mostly because a covered kettle can inflate the temperature of the wort above boiling temperature, causing your sugars to caramelize at the bottom of the pot.

In my case, I'm a stovetop brewer using an electric stove, and I'm having trouble keeping my wort at a high enough temp to maintain a rolling boil. In this case, could covering actually *help* or am I entering a world of pain?

 

[Yooper]

The reason to not cover your kettle isn't due to maillard reactions- boiling is boiling covered or not.

The reason is so that the DMS precursors, SMMs can dissipate out through the steam. Covering the kettle means not allowing that to escape.

Even a partially covered kettle can mean that the steam condenses as droplets back into the wort.

 

[Mainer]

The reason to not cover your kettle isn't due to maillard reactions- boiling is boiling covered or not.

The reason is so that the DMS precursors, SMMs can dissipate out through the steam. Covering the kettle means not allowing that to escape.

Even a partially covered kettle can mean that the steam condenses as droplets back into the wort.

Interesting.
Helpful.
Thanks.

 

[flars]

I boil with the lid mostly on. I can keep boiling temperature applying only medium high heat. I do wipe the condensation from the under side of the lid when big droplets start to form.

I only noticed DMS once. This was when I was boiling with the lid fully on and using all Pilsen malts.

 

[govner1]

The reason to not cover your kettle isn't due to maillard reactions- boiling is boiling covered or not.

The reason is so that the DMS precursors, SMMs can dissipate out through the steam. Covering the kettle means not allowing that to escape.

Even a partially covered kettle can mean that the steam condenses as droplets back into the wort.

^^^^This! Plus you lose the benefit of wort concentration.

 

[flars]

^^^^This! Plus you lose the benefit of wort concentration.

What is wort concentration? Do you mean the boil off rate may be too low?

 

[govner1]

If you look at your recipe(s) you'll see that there is a pre-boil gravity & a post boil gravity (OG). This is indeed related to your boil off rate.
Along w/ helping eliminate DMS & SMMs as pointed out by Yupper your boil gets you to your desired OG prior to pitching your yeast.

 

[day_trippr]

What is wort concentration? Do you mean the boil off rate may be too low?

That's what was meant.
But boil-off is only "too low" if it wasn't accounted for in the recipe...

Cheers! (And then there's the whole "low boil-off" movement to consider )

 

[flars]

If you look at your recipe(s) you'll see that there is a pre-boil gravity & a post boil gravity (OG). This is indeed related to your boil off rate.
Along w/ helping eliminate DMS & SMMs as pointed out by Yupper your boil gets you to your desired OG prior to pitching your yeast.

Very true unless you are brewing an extract recipe.

 

[Mainer]

I'm trying to convince the missus that the best way to solve this problem and keep me from dirtying the stove is to buy a Blichmann BoilerMaker. A mere $450 and all our problems are solved! I literally pulled the infomercial "how much would you pay for this? $1,000? $2,000? $5,000?"

Will let you know how it goes.

 

[TopDeadCenter]

A related question...

I'm boiling outdoors on a deck underneath a tree. To keep leaves, twigs, bugs etc. out of my wort I placed a paint strainer bag, previously used for BIAB, over the kettle, essentially a "shower cap" for my brew. It seems like it should allow the DMS to dissipate, while keeping debris out.

Anyone see any problems with this?

 

[jtratcliff]

I think I read somewhere or watched a podcast ... Maybe a brulosophy exbeerimnent... something...
That said covered was OK as long as you had a vigorous boil... Steam escaping from under the lid was enough to drive of DMS precursors and didn't effect boil off rate too much....

I'll look and see if can find it....


Edit to add:

yup, brulosophy: http://brulosophy.com/2016/10/31/the-boil-lid-on-vs-lid-off-exbeeriment-results/


Here's a thread where it's also discussed...
https://www.homebrewtalk.com/showthread.php?t=598893&page=2