Can I get a safe, low-tech, cheap water distiller?
November 16, 2009 7:42 PM   Subscribe

Help me not blow up my kitchen, while simultaneously not spending hundreds of dollars on a water distiller.

I am considering purchasing an AeroGarden (a hydroponics system in which you can grow herbs, vegetables, et cetera). One potential drawback: I have hard tap water, and their FAQ says that's no good. Nor is that same tap water good even if filtered through something like a Brita.

Distilled water, however, is good. So, I searched on Amazon for "water distiller". I was surprised to find high-tech electronic gizmos that cost hundreds of dollars, and nothing else.

It seems to me like I'd just need something like a pot with a tight lid, sitting on the stovetop, with a hole in the lid leading to a tube, with the tube leading to another pot, and that pot sitting in a tub of cold water. It seems to me that this should cost significantly less than hundreds of dollars.

At the same time, I am reluctant to just roll my own based on this vague scheme, due to a desire not to have an explosion when my half-assed creation turns out to fail in a spectacular way under the pressure of boiling.

Is there anywhere I can get a safe version of this sort (or some other sort) of low-tech distiller, for a reasonable price?
posted by Flunkie to Home & Garden (14 answers total) 2 users marked this as a favorite
You can find plans for stills designed for alcohol distillation. These will work just perfectly, provided you use a heat source capable of boiling water.

I made one in high school (for brandy, not for water) that was just a vessel with a coil of copper tubing coming out of it. Worked just fine.

Don't let it boil dry, though. The mineral scale on your boiler vessel will be damn-near impossible to remove. Likewise, you don't want to do this on your stove. You want the water to just barely boil. If you boil it too hard, you'll just shoot water up your condensation coil, ruining your batch. As a result of the gentle boiling, it'll take a while to distill a sizable quantity of water. I'd use an immersion heater, personally.
posted by Netzapper at 7:51 PM on November 16, 2009

for around $200, you can get an EasyStill from BrewHaus.

Basically what you want to make is a moonshine still - only without the explosive alcohol vapor to contend with. However, a leak in a homemade water still would mean hot steam everywhere, and that's just not fun. I would counsel against building one yourself unless you have a bit of experience soldering and do a bit of research on how these things are built.

If you DO decide to build a still yourself, one note - you need to cool the tube leading from your pot-with-hole-in-lid - this tube is called a "worm" - so that the distilled water does not emerge as steam.

There's a lot of information on building a still here, though their focus is primarily on alcohol, I believe.
posted by dubold at 7:51 PM on November 16, 2009

If you are handy it is perfectly possible to build a safe distilling apparatus. Home still setups that are totally not for illegally brewin' your own hooch will distill water perfectly well. If you search home distilling you will find all kinds of crap.

I have to say I am one hundred percent sure that unless you really want to own a still your purposes will be better served by purchasing distilled water from the grocery store. It will be a fairly minor component of your cost. Small scale distilling is a pain in the ass and is very energy inefficient.
posted by nanojath at 7:55 PM on November 16, 2009

The cost to keep your still running is going to be far higher than buying a 25 cent gallon of filtered* water from a vending machine outside your local grocery store once a week.

*look for a vending machine that says their water has been run through a reverse osmosis unit. I have uberhard tap water (TDS 320PPM) but the Glacier vending machines render that same water down to 3 PPM which works just fine in my Aerogarden**.

**I have a SpaceSaver6***. At the height of plant growth, it consumes a little over a gallon of water/week. During the seedling stage, a gallon lasts 2-3x that.

***The thing you really want to save your money up for is the stupid proprietary AeroGarden lightbulbs. Aerogarden recommends replacing them every 6 months, at $20/bulb. Bleah.
posted by jamaro at 8:11 PM on November 16, 2009

I've got to agree with nanojath. By the time you account for the cost of water, fuel, and your nifty invention, you could probably buy 200 gallons of super-market water. And it comes in handy bottles, not in pools on the floor.
posted by Old Geezer at 8:15 PM on November 16, 2009

How much water are you really going to need? I think you need to weigh the cost of a distiller versus the cost of just purchasing gallon jugs of commercially distilled water (available at just about every drug store and most groceries, at least in my area). They are typically between 50¢ - $1 / gal, I think.

Sometimes it's better to pay upfront to reduce ongoing costs, but this strikes me as a situation where it's going to be very hard to beat the price of the industrially-produced product, especially if you factor in the energy costs of doing it yourself as well. (Keep in mind both direct energy costs — gas/electricity for the heat source — and indirect costs, like increased cooling costs during the summer as a result of all that heat. Distillation is an extremely energy-intensive process.)

I think I would do your gardening with store-bought distilled water, at least for a while (maybe the first season) before deciding to invest significant money in a distillation setup.
posted by Kadin2048 at 8:17 PM on November 16, 2009

The reason they'll be telling you that hard tap water is no good for hydroponics will be that it will mess up the pH of whatever nutrient mix they supply as standard. Provided you fix that, a bit of extra calcium in your water will do your plants no harm at all. Lime deposition is not going to be any worse of an issue than deposition of assorted nutrient salts.

If I were in your shoes, I'd just get a pH test and a one litre jug, and test the tap water, and add phosphoric acid drop by drop until the pH tests at 7.0. Then I'd just mix that same amount of phosphoric acid into every litre of water before adding the rest of the nutrient mix.
posted by flabdablet at 8:56 PM on November 16, 2009

You should just try out your plain tap water and see what happens. Seeds are cheap...
posted by gregr at 9:34 PM on November 16, 2009

How about a solar distiller? Cheap and easy, and no worries about explosions.
posted by Solomon at 10:10 PM on November 16, 2009 [1 favorite]

For $197 you could get a countertop reverse osmosis filter which is arguably going to give you purer water than a still since it also has the carbon pre- and post-filters (FAQ).

But I agree that the amount of time it would take for something like this to pay itself off compared to the grocery store water is huge.
posted by Rhomboid at 12:56 AM on November 17, 2009

How much water are we talking about? Because you can make a very simple but effective still using stuff from your kitchen:

Get your largest pot. Put a high rack in the bottom, then sit a bowl on the rack in the middle. Find a round-bottomed stainless mixing bowl that's larger than the top of the big pot. Fill the stainless bowl with water, then freeze it.

Pour whatever it is you want to distill into the large pot. Sit the bowl of frozen water on top. Heat very gently. The steam will rise, condense on the bottom of the frozen bowl, run to the centre then drip into the bowl on the rack. Mmm - bootleg gin.
posted by obiwanwasabi at 2:27 AM on November 17, 2009

Maybe this defeats the purpose of a controlled indoor environment, but wouldn't the cheapest solution be to use rain water? Do you live somewhere it rains/snows enough that you could set out a barrel or a bucket?
posted by MasonDixon at 6:31 AM on November 17, 2009

Nevermind. HYDROPONIC. Sorry haven't had my coffee this morning.
posted by MasonDixon at 6:34 AM on November 17, 2009

The claim that hard tap water cannot be used in hydroponic gardening is absurd and untrue. If AeroGarden really claims that its products will not work without distilled water, then now is the time to look for alternatives to AeroGarden products.
posted by gum at 7:56 AM on November 17, 2009

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