Are there any substantial downsides to having a pot lid with strainer holes?

Bring a small piece of tin foil to wrap over the holes.

The lid won't pop off when the water boils. I like the holes in the lids that I have that have them.

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@Rodger Dodger,
I'm not sure that I follow your logic.

My lid has diameter of 5.75 inches, and therefore a total area of: 25.96 square inches

I would use a 1/16 inch drill bit to make the strainer holes, so each hole would have an area of: 0.003 square inches

Let's just say that I will make 10 strainer holes in the lid (because this is a conservative estimate), giving a total strainer area of: 0.03 square inches

This is only slightly more than 0.1% of the total lid area.

But it seems that what you are arguing is that putting these strainer holes in the lid would basically lead to as much heat escaping at not having a lid on at all.

So in essence, what you are saying, in this case, is that a pot opening that is 99.9% covered will bleed as much heat as a pot opening that is 0% covered.

Do you stand by this assertion?

Having a loose lid (steam coming out from around the rim) with or without drain holes I would think it makes very little difference.
There is a simple way to work that out.
Make a lid out of thick al foil (or fold a thin one in two…)
Shape that over the pot and on your stove at home with a medium setting time a boil.
Do that a few times and get an average. (if you can be bothered)
Repeat with the same temp tap water (make sure the pot is cold every time before you start) now having a few holes in the al foil.
Compare times…

Yes, you are missing something.

It is not the "steam heat retention" waste – as another poster put it – that would pose a problem with your sieve of a lid.
It is the inability to create – and maintain – higher pressure (generated by the steam). That is what the non-holed lid does for you today. Ever seen a pressure cooker? This higher pressure under the lid helps the water to boil at a lower temperature. Meaning sooner.

Once you punch the holes, you will never reach the previous pressure. Your logic of removing only 0.1 % of the lid area may sound good to you, but if it was me, I'd follow the advice Franco gave and start with fewer holes and measure the boil times trying to keep them close to what they were with the solid lid.

Otherwise, the tradeoff is that you would carry more fuel for your stove, and wait longer for your dinner….

> So in essence, what you are saying, in this case, is that a pot opening that is 99.9%
> covered will bleed as much heat as a pot opening that is 0% covered.
This may be so. Laws of Physics.

You see, if the stove is only creating so much volume of steam per minute, and the holes will let that much steam escape with only a (say) 1 mm pressure drop across the lid, then there is almost no difference between the two cases.

Mind you, if the stove is roaring away the pressure drop needed may be a lot larger. In that case you may find there is less heat loss. If there are no holes in the lid the steam will probably leak out at the rim when the pressure gets high enough. If there is no lid then the 'hole' is the diameter of the pot. In all cases you are going to lose heat.

What would concern me far more is the proposed size of holes: 1/16". I don't care how many of those you have, pasta is going to block them all very quickly! You would need much bigger holes. Me, I just use a bit less water, and I don't waste it.

Cheers

" 1/16 "

Much larger than this, and rice grains would flow out. I hate that.

–B.G.–

"This higher pressure under the lid helps the water to boil at a lower temperature. Meaning sooner."

I think you are getting confused or are missing something here Ivo.
The boiling point of water increases when it's under pressure.

That's why cars have a pressurised cooling system, so that the coolant doesn't boil under normal conditions.

It's also why water takes longer to boil at altitude.

In answer to the op's question.
Yes it will make a difference but we are talking a margin that very very few people would notice, we're talking a few extra seconds to a boil time.

"It's also why water takes longer to boil at altitude."

This is incorrect.

Atmospheric pressure is lesser at higher altitudes. Thus the boiling point of water is lower at altitude, resulting in faster boils at lower temperatures.

This would make a pressure-providing more necessary though. By increasing the pressure you raise the boil temp, thus resulting in hotter water to cook your meals with.

I suspect the holes will have little effect on heat retention but if your lid really was providing that much pressure it could result in a lower boiling temp, thus less hot water. I suspect this difference would be negligible though.

If you wanted to find out, just run Franco's experiment, only stick a thermometer in there at the end to see what temps you achieve.

A pressure cooker builds up pressure, but you need a pretty substantial lid and pot. Regular backpacking pot won't have significantly higher pressure inside.

If you're just bringing water to boil and you want lid so it boils faster and conserves fuel, then a few holes in the pot won't make much difference. You want to contain currents of hot air/steam, especially as it approaches boiling. The steam condenses on the inside of lid which releases some of the heat, which will stay inside the pot rather than be carried away in the air.

When it boils, a lot of steam will be generated which will go out any holes, but if there weren't holes the steam would exit around the edge, unless it was a pressure cooker. But for backpacking, you turn it off as it approaches boiling so this is a non issue.

I find it interesting that both the Jetboil Sol and the MSR Reactor 1.0 L. have strainer holes, as well as other holes, in their lids. These are two of the most fuel efficient (and quickest) stoves available. If you turn the stove off at the first sign of boiling, like Jerry suggests, then I don't see that there is much of a downside to strainer holes.

Yeah, I agree with Jerry. There will be little difference between a regular lid and one with even 8-9 1/16" holes in it. Vapor preasure is increased in either case pretty substantually due to the increase in humidity. Condensation will still occur regardless of the area of the holes. What will not happen is the slight increase in pressure while cooking. It might take about 15:05 to cook something that would otherwise have cooked in 15:00 minutes.

What we are looking at is the surface area of the top. If we consider this to be 100% of the condensation (it isn't, some occurs on the sides, some will actually re-evaporate into the air, and so on) then for a 130mm pot (roughly 5") with 10-2mm (roughly 1/16") holes we have: (pi*65*65)-10(pi*1*1) or 13273.2290-31.4159 or around .2%.

.2% is not enough to notice stuff while camping.

Just to clear up one thing – backpacking stoves don't work via the principles of a pressure cooker, at least not the ones we are talking about, or any lightweight one's I have ever heard of.

Yes you WILL lose heat via steam escape if you have holes in the lid. This is in fact the number one way heat is usually lost during the the boiling process, as well as in the re-hydration process if you are doing that. The more steam you see escaping the more fuel you are wasting. For example, way before you even bother with a cozy for re-hydration you should focus on sealing off the steam.

That said as Roger and others pointed out, having a few small holes is not too bad heat-loss-wise, and it allows for controled equilibration of the pressure. When boiling the steam is going to push out through the space around the lid, so you effectively have holes there too. If you are minimizing this subject to the constraints you are working with (if you really need a strainer then you need one), then you are doing the right thing. Again it has nothing to do with the pressure which is basically gong to be more or less in equilibrium with the ambient pressure unless, as was pointed out, the lid is clamped on or very heavy.

Pots lids like the jetboil ones, that grab on, presumably to catch the consumer making an impulse buy thinking it looks like a nice "self-contained" system, are ill-conceived IMO. But ill-conceived or no, they require holes so they don't fly off like a popgun half way through. I'm sure someone on the design team said "hey, if we add a few *more* holes we can tell them its a strainer". The result is a very heavy lid, and slightly more inefficient. Its a big price to pay every time you do a boil for the few times you need to strain something, and that just so you don't have to be a little careful when doing it with a normal lid. Fortunately the jetboil is at least a good fit for 1 cup ziplock bowl lids, and so a perfect substitute is available.

So for stove efficiency all you need need for a lid is something to minimize the steam escape, so the lightest thing that can take the heat, that "seals", but is loose-fitting enough to let the pressure equilibrate without anything untoward happening to causes a mess or scalded appendages.

With a loose-fitting light lid just put a rock or you spoon or something on top. If there are gale force wind you might have an issue, but it might be the least of your cooking concerns at that point.

No

Above about 185F most of your heat loss is from steam escaping. You want to cover your pot to prevent that steam from escaping. I don't think it's a percent-covered thing – as soon as you put any tiny pinhole in your lid any hot steam that wants to escape is going to find that tiny pinhole. How many pinholes until you actually notice a difference? I think you need to experiment. I would suggest the boiling experiment mentioned above – lid tight vs. lid slightly ajar.

But your big loss in efficiency wouldn't likely be in boiling time, it would be in rehydration time. When I cook noodles, I put them in water until the water almost boils, and then turn off the stove and put the cover on tightly for 10min and let the heat of the water cook the noodles. Some people use a pot cozy for that. If you have any pinholes at all in the lid during that 10min, I think you would see a lot more heat loss. Maybe. So really, the experiment you want to do is not boiling time, it's cooling off time – how hot is the water in the pot after 10min after the stove is off, strainer holes vs. no strainer holes. If you do that experiment, try it with a pot cozy too. You'll discover that pot cozies do essentially nothing unless it's windy or you are sitting on snow – it's all in the lid.

All that said, I'd stick to chicken noodle soup and not waste the water.

Interesting discussion. Needs some empiricism…test and see what happens. That will put half this discussion to rest!

> With a loose-fitting light lid just put a rock or you spoon or something on top
Top of the pot on the lightweight lid is where I keep my pot lifter. Perfect solution to two problems.

Gale force winds are OUTside the tent. I am INside. :-)

Cheers

"Gale force winds are OUTside the tent. I am INside."

LOL @Roger, yeah I was thinking exactly that too when I wrote it. But I think seeing the kinds of qualifications people counter with some times on here has turned me into a lawyer.

"This higher pressure under the lid helps the water to boil at a lower temperature. Meaning sooner."

Water boils at a higher temperature as the pressure goes up. Pressure cookers allow you to cook at a higher temperature.

There is some pretty appalling physics being bandied about in this thread that I am not used to seeing on BPL.

First, when atmospheric pressure goes up, the boiling temperature goes (the opposite is also true…. they drop together). Water boils at a lower temperature at elevation.

Many people have suggested that drilling a couple holes in the lid will have disastrous effects on the heat loss from the pot. The lid is presumed to build up pressure in the pot thereby increasing the boiling point in the pot. Let's see how much pressure gets built up. I did some googling and found typical lightweight pot lids weigh around an ounce (1/16th of a pound). Earlier the op said his pot lid has a surface area around 26 sq in. It would take a pressure difference across the lid of 1/16 lb / 26 in sq = 0.0024 psi to lift the lid and allow the steam to escape. That is how pressure you can build up in your pot by putting a lid on it. That will raise the boiling point in your pot by about 0.008 deg F. Quite the pressure cooker.

As someone mentioned, the lid acts as a barrier to allow humidity to build up near the liquid surface. That reduces the amount of evaporation heat loss. As long as your hole are small enough (or few enough) that you don't get a breeze into your pot, it won't affect efficiency in any measurable way.

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First , again, I am highly amused about how something that it is so simple to verify needs to be turned into a highly complex scientific debate.
Makes me wonder if many here ever cook at home .
For example "straining " rice.
Who does that ?
(hint : to cook rice 1 cup of rice = 2 cups of water, no wastage no trowing away some of the already small nutritional value)
Next : a bandanna (!)
Do you seriously propose using something I wipe sweat with and is exposed to dirt and oils to strain pasta with ?
Cheesecloth ?
So that I spend 10 minutes after washing it or shall I just let it build up bacteria so as to lose some body weight the next few days ?

If one is really desperate to save 1/4 of a gram of fuel, well just put a flat pebble or piece of wood on top of those holes.

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