I've just reduced a 4l of stock in my "kitchen" to 0.5l by boiling it over an hour.

I wrote "kitchen" with quotation marks, because that room might have been designated as a kitchen when the apartment was being built, but I'm pretty sure I see a lot of sagging paint on the ceiling that wasn't there before, the windows in all the rooms in the apartment look like it's just been raining inside and all the sachets I keep in the spice cabinet are wet.

Is there something I could buy that would collect the steam from boiling and prevent this from happening again? The obvious answer would be to install a hood and connect it to a vent (which is conveniently located at the exact opposite point to where the stove was installed), but that would easily set me back a few $1000 and what I can afford right now is more in the range of $60.


Is there something I could buy within $60 range that could handle collecting steam from 3.5l of evaporated water boiled within one hour? Maybe a dehumidifier made specifically for kitchen or a special lid that allows evaporation but collects the water? If it helps, I'm located in Poland and the price range is actually around 280 PLN.

  • 7
    Fan in window, drawing air out?
    – moscafj
    Commented Nov 18, 2022 at 0:30
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    @moscafj that can be a solution for summer, today was 0 degrees C and the temperature is going down rapidly with each day. I don't fancy opening the window for one hour in this temperature. Commented Nov 18, 2022 at 0:55
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    Do you have a fan in the vent located exactly opposite the stove? Did you use it?
    – Ecnerwal
    Commented Nov 18, 2022 at 1:44
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    The classic chemistry way to do this is with a vapour trap - basically have the steam pass through a cooled chamber of some sort (usually done with an ice bath and a retort). This chamber would need to attach to the pot lid and vent into the open air. I've never seen one for cooking, but I haven't looked, and it would likely be simpler to just have a tube that vents to open air.
    – bob1
    Commented Nov 18, 2022 at 3:33
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    Since it's cold outside, it wouldn't take much more than 2 minutes to ventilate the whole apartment by opening all windows at once. After 2 minutes, you'd have removed a lot of the indoor humidity, and your walls, furnitures and pot would still be warm. Do it every 15 minutes, and you might not have to buy anything. Boiling so much water inside, with no ventilation at all is a recipe for disaster. For your walls and your lungs once mold has grown. Commented Nov 19, 2022 at 4:56

5 Answers 5


Well, what you’re looking for is called a “still”. It boils liquid and condenses and recovers the vapor. Most commonly (in cooking) a still is used to boil off and collect pure alcohol, but stills I’ve seen are also capable of boiling off water — in fact, in places where stills are legal to own but alcohol distillation is illegal, distilling water is the excuse under which stills are commonly sold. But it really will work for you; you’ll end up with reduced stock and some distilled water.

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    I can find stills twice as large as my pot for almost exactly $60, this is the accepted answer. My DIY solution is also basically a still, but parts come at 1/3 of the price, so I need to consider which one I would prefer. Commented Nov 18, 2022 at 10:50
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    It's lucky you're in Poland, where it appears you can buy stills readily. Even searching for just condensors from the UK I'm mostly getting Polish suppliers. But if you can find a Leibig or Graham condensor the rest can be done with hose and plumbing hardware, drilling a hole in a well-fitting pan lid.
    – Chris H
    Commented Nov 18, 2022 at 14:27
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    @ChrisH that's interesting to hear, since alcohol distillation without a license is illegal here, even for home use. Those I found on the local internet were labeled as double puropse still + "szybkowar", which is a kind of traditional pressure cooker, so maybe their use in cooking is why they are historically more common here. Commented Nov 18, 2022 at 18:59
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    @ReverentLapwing The off-the-shelf solution doesn’t necessarily offer a lot of benefits beyond the DIY solution. It mostly depends on whether you feel confident in your DIYing skills (and whether the still would be useful to you more generally).
    – Sneftel
    Commented Nov 19, 2022 at 0:26
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    @EricDuminil so long as the heat doesn't just go down the drain. (Lab) stills I've used cool the condensor with cold water, then both the warmed water and the condensate drain away
    – Chris H
    Commented Dec 21, 2022 at 20:55

It's probably a little more than your budget, but I run a dehumidifier in my kitchen in the winter. The utility room is adjacent and that's where I hang my washing up to dry so even without long simmering it gets pretty humid in the kitchen. With the dehumidifier I don't need to use the extracting cooker hood for boiling (just for frying).

It helps with keeping the place warm, because as well as reducing the need for ventilation it recovers heat by condensing water. Mine collects 2-3 litres of water per day.

If your apartment is prone to condensation anyway a dehumidifier will help, leaving internal doors open, but in this case I would shut the kitchen with it in there. I might even put it up on the worktop pulling moist air from the area of the stove when reducing large quantities - it's most effective at reducing the humidity of warm, humid air. Even so a small model wouldn't keep up with the boil-off rate you have, but it would make a big difference and bring the humidity down much quicker afterwards. Slowing the rate at which you're reducing the stock would make its job easier.

Mine has a compressor like a fridge, and makes a bit of noise. There are some with thermoelectric heat pumps but I don't expect them to be as good, and you'll still get fan noise.

I tried something else, hinted at in your question, and compatible with the dehumidifier, but it didn't work: A non-stick steel baking sheet angled as if to deflect the flow of steam into a dehumidifier soon collected quite a layer of condensation. Unfortunately it reached an equilibrium where no more water condensed, with just too little on there to run down into the waiting jug. Touching the back it felt like only about 40°C. Possibly a more thermally conductive sheet (aluminium) with a fan blowing room air on the back to cool it would condense enough to drip, and could be used to augment a dehumidifier.

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    I don't think a dehumidifier will keep up with the pace of vapor being produced.
    – GdD
    Commented Nov 18, 2022 at 9:48
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    @GdD boiling off 3.5l in an hour possibly not, though the higher the humidity the more effective the dehumidifier (that's why I'd think of putting the dehumidifier inlet near the source of steam). It will still be far better than the current situation and the humidity in the home will drop far faster after turning off the heat than with nothing. Unlike inefficient ventilation from opening windows you won't waste all warm air
    – Chris H
    Commented Nov 18, 2022 at 10:04
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    ... some data on the effect of increased relative humidity on the efficiency for a model comparable to the rather old one I have. Note that my kitchen rarely gets over 18°C in winter so I won't be able to collect as much
    – Chris H
    Commented Nov 18, 2022 at 10:18
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    @ReverentLapwing not only doubling your budget now but also costing a LOT on your next electricity bill. Dehumidifiers just soak up Electricity
    – Hobbamok
    Commented Nov 18, 2022 at 22:15
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    @Hobbamok I use mine quite heavily in winter and have electricity and gas bills well below average for my size and age of house. They give useful heat (shifting some gas consumption to more expensive electricity) and reduce the need for ventilation, saving quite a lot of energy. They're also far more efficient than electric clothes dryers except heat-pump models, or in my case mean I can dry laundry easily. My climate is a little warmer than the OP's but I still have to heat the house nearly half the year
    – Chris H
    Commented Nov 19, 2022 at 9:05

Get a portable induction cooktop. Put it underneath the existing vent and do your high-humidity cooking there.

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    Why would the cooktop being an induction cooktop be relevant?
    – Sneftel
    Commented Nov 18, 2022 at 23:12
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    @Sneftel, safer than a resistive cooktop.
    – Mark
    Commented Nov 19, 2022 at 3:48
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    @Sneftel And because they're portable and can be moved wherever the ventilation is best, or even outside.
    – Dan C
    Commented Nov 19, 2022 at 14:09
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    @Sneftel They're more popular right now than other types so you can get a decent one with limited budget. Commented Nov 19, 2022 at 23:10
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    I have induction stove and it was within the specify budget. But moving it didn't work, there is barely any pull from the vent, even after cleaning it. Commented Nov 20, 2022 at 9:17

Figure out a way to hold an umbrella over the pot, and then either put a cup under the tip of each rib, or put the whole assembly over a large tub or tray

  • The caveat would be it/they'd need to be high above the boiler (heat and cheap plastic don't mix!), and carefully secured, lest it/they fall and become even more of a fire danger. Plus, the question is whether they'd be able to condense water quickly enough to put a real dent in things before the resulting air moves away from the setup (as convection up and then out will be fairly rapid). But an interesting idea. Commented Nov 20, 2022 at 2:03
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    This would be nearly completely ineffective.
    – Sneftel
    Commented Nov 20, 2022 at 9:43

Got Polish winter? Use Polish winter!

Freeze distillation removes water from a solution. Ice is pure water and as it freezes the remaining unfrozen liquid is more concentrated - with alcohol, or with delicious stock flavors.

From Wikipedia

Freeze distillation is a misnomer, because it is not distillation but rather a process of enriching a solution by partially freezing it and removing frozen material that is poorer in the dissolved material than is the liquid portion left behind

Leave your stock pot outside. Bring it in periodically and remove ice.

Bonus: you will not cook delicate dill and carrot flavors into oblivion with a 4 hour boil.

I must admit to being a little bummed that this awesome stock scheme stands at -1. There must be other skeptics. Here is some back reading as regards the freeze approach for concentrating liquid foods. Maybe they will explain it better than I did.

Freeze concentration techniques as alternative methods to thermal processing in dairy manufacturing: A review

  • This doesn't make sense. In alcohol distillation, you have two solvents, alcohol and water, with alcohol having a lower melting point. In a broth, you either have a single solvent (the water), or two solvents, water and animal fat. If you have fat: the animal fat freezes at above 0 C, but removing it still leaves you with non-concentrated broth. If you don't have fat: you would have as much taste in the ice layer as in the liquid layer, so you wouldn't be concentrating anything, you would be throwing out parts of your broth.
    – rumtscho
    Commented Dec 22, 2022 at 17:08
  • @rumtscho - suppose we are in Antarctica and the ocean freezes. Is there as much salt in the ice as in the water? No. The ice is freshwater. So too the broth. Ice is pure water that has frozen out of the broth. The broth retains salt and solutes and flavore. Ice is pure water.
    – Willk
    Commented Dec 22, 2022 at 20:57
  • The broth that you want to keep has a lower freezing point than the water you want to remove from it. You use that difference to remove the water as ice.
    – Willk
    Commented Dec 22, 2022 at 20:59
  • I've never been to Antarctica, and I will admit that the theory of such fractional freezing is not my strong point. But practically, when you freeze broth, you don't get two fractions. You just end up with a solid lump of frozen broth, without any evidence (e.g. a color gradient) that it is somehow not uniform.
    – rumtscho
    Commented Dec 22, 2022 at 23:20
  • @rumtscho - yes you can freeze it solid. Also you can freeze alcohol containing liquid solid. The idea is to skim out the pure water ice as it freezes. As you remove pure water ice the remainder is concentrated for solutes that lower the freezing point - ethanol, or salty stock.
    – Willk
    Commented Dec 23, 2022 at 1:57

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