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Homemade Tonic Water Filtration

Today's post was written by Kevin Liu. We were having an email conversation about filtration- he uses a small-pore coffee filter that removes the bark bits when he makes tonic water and I thought that filter might also be good for removing charcaol after clarifying spirits- and I asked him if he'd share his information with us.

Kevin Liu is an editor at ScienceFare.org, a site about cooking with science. Kevin is obsessed with cocktails and science and he's always looking for new geeky ways to get drunk.  You should email him at  kevin@sciencefare.org. 

Take it away, Kevin!

Up until recently, cocktail geeks had few options for good tonic water.  The mass-market stuff uses high-fructose corn syrup, quinine extract, and citric acid and lacks both nuance and depth.  To make a really classy gin and tonic meant DIY-ing your own tonic water. As it would turn out, quinine is a controlled substance in the United States because in large doses it can heart problems, headaches, nausea, and birth defects, to name a few.

Let's not forget that quinine was first prescribed as a treatment for malaria and that gin was used to make it more palatable.  The stuff's no joke, and for that reason, quinine extract (the stuff used in commercial tonic) is not available for purchase.

To make your own tonic, you have to go to the source - Peruvian tree bark, or cinchona.  There are a number of places you can order the stuff from online.  I picked up a pound of it from the Pennsylvania Herb Company for about $30 shipped.  That's pretty steep from some bark, but a pound is a whole lot of tree - just 'sayin.  If you consider a four-pack of "gourmet" tonic water runs about $6... the economic benefits start to become apparent.

The big problem home tonic-makers often run into is filtration.  Powdered cinchona is almost impossible to filter out and the cut-up bark (which is what I used) inevitably contains some powdered material as well.  Cheesecloth and fine-mesh filters won't catch the particles and coffee filters clog quickly.

So I hacked some stuff together. I found a website that talks about really small pore-size (1 micron) filters for coffee.  The guy basically bought a polyester filter bag, cut rounds out of it, and jerry-rigged it into an aeropress coffee maker.  Why shouldn't the same thing work for filtering out cocktail stuff?  ...and it does!

 

Aeropress
Aeropress Coffee Maker


In the original article, the poster recommends substituting the polyester round for the standard paper filter - he files down parts of the aeropress to make it fit.  I didn't want to do this, so I just cut the polyester round slightly smaller than the paper filter and used the two in conjunction.  

 

IMG_6711
Filter image by Kevin Liu
IMG_6712
Filter image by Kevin Liu

The 1-micron filter caught the cinchona bark beautifully; at the end, the filter was a mass of brown gunk and my tonic syrup came out a lovely transparent, sediment-free brown.

The recipe I used was pretty simple - at this point, I just wanted to see if the aeropress could be used with this method as a proof of concept.  With this initial success, I'm planning to move on to more experiments with other flavors, plant materials, and filtration methods.

 

IMG_6722
Filtered Homemade Tonic Water by Kevin Liu

 

Recipe

Combine 20g cut cinchona bark with 1 cup water.  Heat to a boil, then simmer for 20 minutes.  The liquid should reduce/absorb into the bark such that you'll have about a 1/2 cup left.

Strain the liquid first through a fine-mesh metal strainer, then use the aeropress method described above.

Add between 110g and 220g sugar to the cinchona water.  Optionally, add water until you have 2 cups of product to make a 1:4 ratio syrup.

Recipe Notes

I used 220g of sugar to 20g bark and felt that the result was not bitter enough.  With that being said, tonic water desperately needs citric acid for balance (no, lemon juice won't cut it).  Since I didn't want to add any additional flavors to this batch, I really don't know how the ratios will work out in a completed tonic water.  The next steps will be to start adding lemongrass, citrus peels, citric acid, and allspice.  

But I will say that the tonic syrup as described above, 1:4 with soda water, makes a pleasant and sweet gin and tonic.  It goes best with an easy-drinking gin, like New Amsterdam.  A hefty squeeze of lime or lemon gives a nice balance.

---

Thanks Kevin for sharing your experiments! Has anyone else tried this method or something similar?

Note: Coincidentally, Jacob Grier shared his tonic recipe using a different espresso maker today.

Comments

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EricLecours

Is there any way to make the tonic clear like commercial tonics? A brown gin and tonic is just hard to get used to.

carey

Oooo, what a neat idea! I've made a few batches of tonic using the same cut bark from Penn Herb Co. The first couple times I ran it through a cheesecloth-lined fine sieve once, and then "coaxed" it through a paper filter. Not nearly as harrowing as trying to filter out powder, but still a bit tedious. The last time, however, I measured out the bark I needed plus a little bit extra, then placed it in the sieve and gave it a good shaking to get out all the smaller bits first. When I was finished with the batch I just ran it through the cheesecloth twice. It's been stored in the fridge for a couple days now, and there's no sign of sediment! I've also thought that a gold filter might work well for this, provided you can get one with a flat bottom that is also made up of the filter material (and not solid plastic, like some are).

Love that Kevin Liu! I did a post on tonic water a while back and he had some excellent suggestions for people who were asking about sweetener and cinchona substitutions (apparently the latter is nearly impossible to find in Australia and the UK). What a cool dude. (:

MyAmericanDram

I know locally in the bay area Lhasa Karnak carries cinchona bark and everything else you could possible want to use.

I haven't tried it with Tonic syrup, but I have used Brita water filters to filter out my bitters to get rid of any sediment. It's nice because I don't have to stand there and pour the bitters through a coffee filter. I can just pour the liquid in the pitcher, leave and come back later.

I also want to look into using coffee siphons and buchnel funnels to see how they can work when filtering liquids.

Camper English

Not that I know of. As Kevin mentioned, we can't access the industrial-strength stuff.

Ouroboros

In April I filtered a vin d'orange using an Aeropress. It worked really well for extracting the liquid from the steeped sliced citrus.

Jon

Don't know if this would work but probably worth a try, no?

http://www.nytimes.com/2007/09/05/dining/05curi.html

Camper English

I forget where I read it, but someone tried the gelatin/agar method with tonic syrup but felt it sucked out all the flavor as well as the color.

Kevin Liu

EricLecours,

Unfortunately, every thing I've used to try to clarify tonic fully results in a tasteless product. I would definitely like to know how to do it, though, and I'll post about it if I figure it out :-)

Kevin Liu

yeah I tried that :-). And it did suck out the flavor :-(

Ben Simpson

Extract of quinine (which gives you clear tonic)is not that difficult to make from raw cinchona bark, but it does involve some laboratory equipment and assorted acids. The process is demonstrated in an English TV series called 'Victorian Pharmacy'- the result is crystals of pure quinine.

jon gasparini

I have used a buchner funnel numerous times when filtering aromatic bitters. It works very well but you you need to change the paper filter frequently. Still much better than coffee filters because you have the added benefit of the vacuum effect.
This method seems great. Definitely going to give it a shot. Thanks! jg

Alifeinfood

Have you tried a rotary evaporator (Buchi) or a centrifuge? Not that easy to come buy, but worth seeking out surely. Dave Arnold outlines various methods of clarification on his cookingissues.com blog. I imagine if you've been searching for clarification methods, you've already found it...

Issabella

It works very well but you you need to change the paper filter frequently. Still much better than coffee filters because you have the added benefit of the vacuum effect.great thing

Cody P

A comment on the filtering methods I have tried (they all seem to suck and take a long time/a lot of filter changes) is that instead of steeping the bark directly in water, I put the bark into an open ended tea bag and sealed the tea bag. I then got the most "amber" rather than brown colored tonic syrup so far. I think its a cleaner way of doing it too because I have generally had tonic going bad within a few weeks of making it, now this flask has lasted 8 weeks and shows no signs of being past its useable date.

:-)

Camper English

Do you think you get the same amount of tonic bitterness with this method? I continue to be unsure about if these methods extract quinine or just bark flavor *sigh*

Cody P

My tries of doing this with boiling or simmering water have returned very flat profiles for the tonic, I'm guessing this is from taking the bark flavor without much of astringency the quinine provides.

Side note, doing this cold in the refrigerator over a few days yields much more bitter tasting syrup for the same amount of bark. With this method I get a bit of the feel of tannins while drinking it.

Camper English

Interesting, thanks again!

Norm D

Five years late to the game, but better late than never, right? I've used the aeropress filtration method a few times over the years, thanks to your great website.

Some good news to share - I stumbled upon an easier filter. I picked up a pair of metal reusable filters for the aeropress, and figured I'd revisit this method. It went extremely fast, there was very little clean up, and most importantly - no visible sediment in the filtered liquid. For curiosity's sake, I even filtered the sediment dregs at the bottom of the bowl(I usually don't bother for sake of ease and to err on the safe side), and once again the liquid came out with no visible sediment. Hope folks can put this to good use.

Cheers and keep up the good work!

Camper English

Excellent - thanks for sharing your results!
Camper

EthanWilliam

Thank you

Søren

Hello Norm.

Do you know the micron rating on that filter? There seems to be a lot out there of different ratings!

GG_CHS

Hey, just a thought to put out there... i havnt tried this yet, but i may try it in the future... A Cooking technique that may work.
In cooking, When making a highly clarified ‘consome’ (broth) a traditional step is to whip egg whites until fluffy/soft foam, pour on top of liquid to clarify to form a ‘raft’ simmer at a slow/soft boil. The egg whites act as sponge, capturing all the impurities! From what I remember, flavor is not comprimised.

Camper English

Hi- yes this is the same method as making milk punch more or less (I wrote up some of the science of it for CooksScience.com if you want to find it), though I haven't tried it. That does leave some creamy texture to the resultant liquid which may or may not be desirable.

vinish shetty

has any one tried using cinchona extracts available online?
also like making gin why don't you try steeping the contents than boiling it since its the taste and not the color

Camper English

The ones I know of are made for treating leg cramps, so not sure they're pure cinchona or not but that's something to be aware of. The bark is quite dark so you can't really just steep it without it leeching color; would be just less color.

Kennie

How do U differentiate pure cinchona from the other.

Camper English

https://www.cocktailsafe.org/quinine-tonic-water-cinchona-bark.html

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