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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.

Summary

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.

Giacomo1968
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Reverent Lapwing
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    Fan in window, drawing air out? – moscafj Nov 18 '22 at 00:30
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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. – Reverent Lapwing Nov 18 '22 at 00:55
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    Do you have a fan in the vent located exactly opposite the stove? Did you *use* it? – Ecnerwal Nov 18 '22 at 01:44
  • @Ecnerwal there is no fan, but I feel a slight draft when I put my hand to it. I've done a lot of reading since writing this post and apparently it would be illegal to install a fan there or cover it in any way, since there is a gas installation in the room. I don't use gas, but just the presence of the "pipe" and a valve is enough for it to be illegal. Currently I'm tinkering with some ventilation system that would pull the steam with a fan through a pipe submerged in water, so it cools before exiting and doesn't steam up the room. I'd still prefer a readily made product. – Reverent Lapwing Nov 18 '22 at 01:53
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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 Nov 18 '22 at 03:33
  • Note that any form of extraction will draw in cold air to replace it (your existing vent will serve for that). You might want to avoid so much cooling – Chris H Nov 18 '22 at 06:43
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    @bob1 it wouldn't be too hard to make something. A hose fitting in a saucepan lid, a 2nd saucepan with the entry pipe going through the lid down fairly low, baffles in that pan made of foil (so air doesnt flow straight to the outlet). That 2nd pan needs another hose fitting for its exhaust, with a fan pulling on that through something funnel-like (or perhaps better a fish tank air pump). In a chemistry lab you wouldn't use a fan but your vessels would be better sealed. 2nd pan sits in ice water bath – Chris H Nov 18 '22 at 06:50
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    Another suggestion that you can use on top of other ideas, cost near zero: As soon as the windows are wet, open those that you can, use a shower squeegee to clear the water, then shut them (one at a time). Hopefully they open outwards but if they open inwards you'll need to catch the drips on a tray. You won't let too much cold air in by such brief opening. – Chris H Nov 18 '22 at 11:30
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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. – Eric Duminil Nov 19 '22 at 04:56
  • @EricDuminil never tried opening all windows (not just in the kitchen), so I did that yesterday. As always, the draft was blowing the steam inside, not pulling it outside, so I don't think it works. – Reverent Lapwing Nov 20 '22 at 09:21
  • @ReverentLapwing thanks for trying. Depending on building geometry, wind, temperature and pressure, natural ventilation should flow from some windows to others, and not just from outside to inside. Still, if your very humid air from the kitchen has to flow through other rooms before leaving, it might not be the best solution. Especially if you're always adding more steam. The "still" is probably the best solution. – Eric Duminil Nov 20 '22 at 15:55
  • "all the sachets I keep in the spice cabinet are wet" that's really the only problem here. Put something else or nothing in that cabinet. As a renter, condensation rotting wooden framed windows is the landlord's problem, and if there's no fan that's their fault, as is the uninsulated exterior walls that are cold enough to condense water vapor. Also, that hole you feel air coming in is the fresh air intake; do not cover or modify. – Mazura Nov 20 '22 at 23:41
  • 3.5l over an hour? Well, yeah. Simmer, don't boil; give it more time to escape your leaky house. – Mazura Nov 20 '22 at 23:44
  • @Mazura "As a renter, condensation rotting wooden framed windows is the landlord's problem". Wait, what? Indoor humidity very much depends on user behavior. The same flat could have perfectly healthy walls and indoor quality, provided the renter doesn't decide to regularly distribute 3.5kg of water everywhere, with closed windows. I'm all for tenants rights, but in the above case, the landlord would be justified to ask the tenants to repair anything their behavior has caused. – Eric Duminil Nov 21 '22 at 07:11
  • @Mazura "simmer, don't boil" it was a bone broth, so I was actually boiling it on low heat for over 48 hours :D I only had to add maybe a half cup of water over that time to keep the water level. When I actually simmer, don't boil, then over 6 hours of making stock at 90C+ I've never seen the water level go down. It already takes an entire day to make a stock and an hour to reduce on 2000W induction stove, I don't have another day in a day to reduce it on low heat after it's done. – Reverent Lapwing Nov 21 '22 at 08:13
  • @ReverentLapwing: "Entire day" as in 24h or as in ~8h? 48kWh, or even "just" 16kWh of electricity will get expensive pretty fast. – Eric Duminil Nov 21 '22 at 10:50
  • @EricDuminil for long simmer/gentle boil I'm using a cheap resistance coil at level 2 out of 5. 2kW is only for reduction. Max power over shortest amount of time should save electricity, since at 100C the water is losing heat at the same rate no matter how much wattage I put into it. But I don't really care about saving pennies, I was commenting that even on max power it takes one hour to boil all the water out - stock already takes an entire day (morning to evening), I don't need to make it last longer. Water needs to cover everything as it simmers, so gradual boiling off also makes no sense. – Reverent Lapwing Nov 21 '22 at 17:26

5 Answers5

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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.

Sneftel
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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. – Reverent Lapwing Nov 18 '22 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 Nov 18 '22 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. – Reverent Lapwing Nov 18 '22 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 Nov 19 '22 at 00:26
  • As a bonus, the condensing part gives you a lot of energy back, which is desirable in winter. – Eric Duminil Nov 20 '22 at 15:57
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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 Dec 21 '22 at 20:55
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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.

Chris H
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    I don't think a dehumidifier will keep up with the pace of vapor being produced. – GdD Nov 18 '22 at 09:48
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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 Nov 18 '22 at 10:04
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    ... [some data on the effect of increased relative humidity on the efficiency](https://blog.meaco.com/dehumidifier-extraction-rate/) for a model comparable to [the rather old one I have](https://dehumidifierreviewshq.co.uk/delonghi-dem10-compact-review/). Note that my kitchen rarely gets over 18°C in winter so I won't be able to collect as much – Chris H Nov 18 '22 at 10:18
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    This would be an accepted answer if not for doubling the budget, which is already stretched as it is. I've read about some dehumidifiers from my price range and people didn't have many kind words to say. If I ever have some spare money, I will probably buy it. I didn't mention this in the question, but I keep my kitchen warm for the plants growing on the windowsill, so it sounds it would be perfect condition for a dehumidifier. – Reverent Lapwing Nov 18 '22 at 10:56
  • @ReverentLapwing, yes, they've gone up quite a bit since I bought mine about 10 years ago - I thought you might have to stretch maybe 25%. That's disappointing for me as well, as mine has started failing to turn on sometimes. The cheap ones I think are the thermoelectric/Peltier models which might just about be OK in a car but not for a house. I'm considering sketching how I'd make the condenser for a still based on what I have at home, but there are probably designs online already – Chris H Nov 18 '22 at 11:24
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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 Nov 18 '22 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 Nov 19 '22 at 09:05
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    @Hobbamok: Compared to boiling off the water presumably electically as well (since OP says they're not using the gas installation), an electric dehumidifier is low power (200 W vs. e.g. 2kW for the stove). And OP would operate it under efficient conditions (at very high humidity). – cbeleites unhappy with SX Nov 19 '22 at 15:46
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Get a portable induction cooktop. Put it underneath the existing vent and do your high-humidity cooking there.

user3067860
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    Why would the cooktop being an induction cooktop be relevant? – Sneftel Nov 18 '22 at 23:12
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    @Sneftel, safer than a resistive cooktop. – Mark Nov 19 '22 at 03:48
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    @Sneftel And because they're portable and can be moved wherever the ventilation is best, or even outside. – Dan C Nov 19 '22 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. – user3067860 Nov 19 '22 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. – Reverent Lapwing Nov 20 '22 at 09:17
  • @ReverentLapwing That is a bummer. I don't think our vent "pulls" that much from the fan but the main pull is when hot air starts going up it (the same way a smoke stack pulls without any fan, etc.). – user3067860 Nov 21 '22 at 14:41
  • Is your vent maybe not vertical all the way up? If there are bends in it then it basically stops working, if you can make it vertical until the very top opening then it should work better. – user3067860 Nov 21 '22 at 14:51
  • It's a hole in a wall in my apartment that draws air, I don't know what else to tell you. If I can feel it moving air and it passes regular inspections from the chimney men, then I'm sure it's working fine for it's purpose. The purpose, I'm guessing, being not drowning in my own CO2? – Reverent Lapwing Nov 21 '22 at 17:37
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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

Moe
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  • 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. – JeopardyTempest Nov 20 '22 at 02:03
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    This would be nearly completely ineffective. – Sneftel Nov 20 '22 at 09:43
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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

Willk
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  • 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 Dec 22 '22 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 Dec 22 '22 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 Dec 22 '22 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 Dec 22 '22 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 Dec 23 '22 at 01:57
  • I'd guess this method works because freezing point of pure ethanol is -113C. Chicken stock contains two liquids: water and chicken fat. Chicken fat is solid at room temperature. Most of the solids that give stock its flavour are dissolved in water and will freeze with it. I can prove this method doesn't work by simply placing the stock into the freezer. – Reverent Lapwing Dec 27 '22 at 13:17
  • @ReverentLapwing - do, but don’t let it freeze solid. Take it out and swipe out the ice needles every hour. Taste the ice. It will just be frozen water, no stock flavor. Ok rinse it off then taste it! – Willk Dec 27 '22 at 13:23
  • Oh my gosh. Downvotes again. I am going to have to do the experiment and post the results. – Willk Dec 28 '22 at 16:34