Boiling with lid ON

Hi,

Ive read via many sources to alwaysboil with the lid off due to possible build ups of nasties if the lid is on during boil which can negatively affect beer flavour.

Does anyone know what exactly happen when the lid is left on, is there a chemical build up of some kind?

Does anyone boil with the lid on experiencing no adverse effects?

What off flavours are expected with lid on boiling?

Can lid on boiling work if whatever needs to escape is vented evert ten mins or so by temporarily removing the lid?

Thanks :)

coldlager said:

Can lid on boiling work if whatever needs to escape is vented evert ten mins or so by temporarily removing the lid?

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Good question. I'm surprised more research hasn't been done on this aspect, especially by the big boys as it would reduce energy consumption and loss. But maybe it has been done and we just haven't read it. :wha:

You should leave the lid off. Wort produces sulphur compounds during the boil, which should be allowed to evaporate off or they'll produce dimethyl sulfide (DMS) in your beer (http://beersmith.com/blog/2012/04/10/dimethyl-sulfides-dms-in-home-brewed-beer/ )

I don't think opening the lid occasionally is enough, but I have heard of some people partially covering their boiler.

If you're worried about losing too much to evaporation, it's better to adjust your recipe for that or top up with water.

I asked a similar question to this a bit back, my reason was to reduce the pre boil volume so i could accomodate a full boil in my 30+lt boiler without having to liquer back!

I would like to hear the answers from the pro's on here about this one.

I have no issues boiling with the lid on, DMS will be boiled off at 35C, and won't settle on the lid as that is going to be above 35C . . . Pale malt has very little in the way for SMM (The Precursor to DMS) and the same applies to British Lager Malts . . . I suspect that some of the more esoteric malts from the continent, may require harder boiling to convert SMM to DMS during the boil rather than leaving it present in the cooling phase when it is not removed.(My boiler is open at this point).

US Malt is very high in SMM and that is why you here lots of recomendations to boil with the lid off.

If you want to reduce the evaporation from your boiler . . . reduce the power you are applying to it

I always boil with the lid on or at least partially on, it means that once its up to boil I only need 1 element on. :thumb:

If you/I reduce the power it won't reach a rolling boil!
I get a rolling boil from just the 1 ellement too so would have to reduce the power to the ellement through a variable transformer :nah:

Does this reduce the boil off having the lid partially on so you can reduce the pre boil volume?

Sorry to have hijacked the thread "to a point"

Aleman said:

US Malt is very high in SMM and that is why you here lots of recomendations to boil with the lid off.

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Hm, that's very interesting; I've never been brave enough to try brewing with the boiler partially covered in case I ruined the batch.

But I guess the big commercial coppers I've seen have a sort of chimney arrangement rather than just a big open boil.

I boil with the lid on but have a pudding basin on the top with a hole in and use trunking to take the steam out of the kitchen. I always make sure the trunking has a down-bend in it and, at that point there is a hole in it which lets the nasties/condensate drip out into a bowl. So-far no problems at all with the brews.

Andyhull said:

If you/I reduce the power it won't reach a rolling boil!

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Yes It will , With plenty of insulation on a boiler a 2.5KW element is more than enough to boil 30L of liquid. On my small rig I use a 3KW Element in a thermobox and on full I get a volcanic boil.

Andyhull said:

I get a rolling boil from just the 1 ellement too so would have to reduce the power to the ellement through a variable transformer :nah:

Click to expand...

Which is what I do (Although I use a Burst Fire Rectifier) on the small rig . . . the big rig (150L) is gas powered and I only use the small ring on the Paella Burner (turned down) to boil.

Andyhull said:

Does this reduce the boil off having the lid partially on so you can reduce the pre boil volume?

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NO! having a lid on does not reduce the 'boil off' as it still boils off at the same rate, but condenses and drips back into the boiler, so the thermal loading (as measured by the evaporation rate) is the same, but the boil off is less (evaporation is the same :wha: )

When brewing you want to aim for a (true, lid off) evaporation rate of around 10-12% per hour, more than this and you are increasing the thermal load on the beer, which causes excessive darkening, caramelisation melanoidin production etc etc, at the same time you don't want to drop it too low otherwise you get poor break formation, low hop utilisation.

Most 2.5 to 3KW boilers have a true evaporation rate in the order of 20-30% an hour :whistle: :whistle: so really should have some form of power controller on them

Aleman said:

Andyhull said:

Does this reduce the boil off having the lid partially on so you can reduce the pre boil volume?

Click to expand...

NO! having a lid on does not reduce the 'boil off' as it still boils off at the same rate, but condenses and drips back into the boiler, so the thermal loading (as measured by the evaporation rate) is the same, but the boil off is less (evaporation is the same :wha: )

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So having a lid on does not reduce the boil off but the boil off is less. :wha: I think you are saying that the same amount evaporates but you don't lose all of that, which I think is what Andy was asking.

rpt said:

Aleman said:

Andyhull said:

Does this reduce the boil off having the lid partially on so you can reduce the pre boil volume?

Click to expand...

NO! having a lid on does not reduce the 'boil off' as it still boils off at the same rate, but condenses and drips back into the boiler, so the thermal loading (as measured by the evaporation rate) is the same, but the boil off is less (evaporation is the same :wha: )

Click to expand...

So having a lid on does not reduce the boil off but the boil off is less. :wha: I think you are saying that the same amount evaporates but you don't lose all of that, which I think is what Andy was asking.

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:thumb: Spot on that man!! The important factor is the thermal loading which is the same . . . unfortunately the only way we have of measuring the thermal loading is through the (open Lid) evaporation rate. It is always work doing a few open boils to determine the true evaporation rate so you can decide if the thermal loading is excessive . . . and then take steps to control it.

:? :? :? :?
So i could boil with the lid mostly on with say a 2" gap still get the same evaporation rate but due to condensate on the lid it would drop back in and i would not need such a large pre boil volume?

If this is correct would this still eliminate the off flavours that can occur?

Also if im reducing the power to the ellement will this not put more strain on the pre controll cabling?

Well Ihave just finished a volcanic boil on one tesco 2.5KW element with 60L of wort just covered over not insulated. Used 2 to get it up to boil though for speed but then alternated between the two. Plenty of cold break came out as well so job done :thumb: :thumb:

So you had your boiler top just covered?

I have the 2 tesco ellements on my boiler and as you say will use both to get it boiling and 1 for a continuouse boil.

Andyhull said:

:? :? :? :?
So i could boil with the lid mostly on with say a 2" gap still get the same evaporation rate but due to condensate on the lid it would drop back in and i would not need such a large pre boil volume?

If this is correct would this still eliminate the off flavours that can occur?

Also if im reducing the power to the ellement will this not put more strain on the pre controll cabling?

Click to expand...

I always boil with my lid half on and have never had any problems at all!

Andyhull said:

So you had your boiler top just covered?

I have the 2 tesco ellements on my boiler and as you say will use both to get it boiling and 1 for a continuouse boil.

Click to expand...

Yes Andy one element lid on. The lid actually was slightly cracked open but I got a fantastic rolling boil with one element.

graysalchemy said:

Andyhull said:

So you had your boiler top just covered?

I have the 2 tesco ellements on my boiler and as you say will use both to get it boiling and 1 for a continuouse boil.

Click to expand...

Yes Andy one element lid on. The lid actually was slightly cracked open but I got a fantastic rolling boil with one element.

Click to expand...

:thumb: :

Aleman said:

Pale malt has very little in the way for SMM (The Precursor to DMS) and the same applies to British Lager Malts

Click to expand...

It's never as straight-forward as the book suggests. I've always boiled with the lid off in fear of DMS but will change my practices.

Thanks for asking the question.

After searching the forum and interweb for affects of boiling with lid on back in mid Feb, I was unable to find a definitive answer to my quesion. I decided to experiment for myself, I also then submitted this post to see what peoples opinions would be on here.

I made a simple brown ale (recipe below) and boiled for one hour with the lid fully on for the entire boil, removed brielfy for each hop addition. The control for this experiment is the previous batch i've made to this recipe a few days prior, boiled with the lid OFF which taste good.


Lid ON Brown Ale:

Original Gravity (OG): 1.036 (°P): 9.0
Final Gravity (FG): 1.011 (°P): 2.8
Alcohol (ABV): 3.30 %
Colour (SRM): 15.6 (EBC): 30.7
Bitterness (IBU): 28.6 (Average)

89.55% Maris Otter Malt
5.97% Chocolate
4.48% Wheat Malt

1.1 g/L Fuggles (6.2% Alpha) @ 60 Minutes (Boil)
2.2 g/L Fuggles (6.2% Alpha) @ 5 Minutes (Boil)

Single step Infusion at 66°C for 60 Minutes. Boil for 60 Minutes

Fermented at 20°C with Danstar Nottingham for 1 week

Brewed: 17-02-2013
Bottled: 24-02-2013 (16-22c)

Notes: 2/17/2013 11:06:30 AM :

Water
Total: 5.7L
Strike: 3.69L
Sparge: 2.0L @ 76C

Grain
Maris Otter 600g
Chocolate 40g
Wheat 30g

Hops
Fuggles 5 grams @ 60 mins
Fuggles 10 grams @ 05 mins
Recipe Generated with BrewMate



Question: Does boiling with the lid ON adversely affect a beers taste?

Verdict: NO

Comment: The beer tastes great, I can detect no difference between a lid on and lid off batch. Although the beer is a bit young at the moment and it's flavour will develop there are no detectable off-flavours.


I am happy with the taste of this beer and would not hesitate to boil with lid on in future. For those who need to keep the lid on to achieve a stronger rolling boil on a weak eleccy stove but are worried about all the horror stories, just give it a go and see if you can notice any difference. To increase the accuracy of this experiment you would brew two batches side-by-side, lids on / off, however, my setup restricts me from doing this.

Thanks for your input guys. Hope this helps someone with the same question in the future.

Cheers :