Coffee News: from Seed to Cup

How to Get Crystal Clear Coffee—Without Filter Paper!

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I have a confession to make: I HATE using filter paper. It clogs frustratingly fast, it’s expensive, it’s a single-use item, and worst of all, half the time it doesn’t even do that good a job. Sure, you can use a filter aid or multiple filter setups to overcome clogging issues, but that’s a pain. In short, using filter paper for anything is a complete drag.

SEE ALSO: How To Make 60 Second Cold Brew—Without Nitro

In the pursuit of the cleanest, clearest coffee, I spent months of research trying to crack the best way to filter. I’ve tried ceramic filters, metal filters, racking, fining, egg whites, enzymes, distilling, centrifuging—you name it! I had an incredibly unhealthy obsession with clarification techniques for the longest period of time.

But in the end, I settled for a process that is not only quick and easy to do, but also economical: agar clarification. No idea what that means? Bear with me, you’ll understand soon.

“Why clarify? Why breathe?” – Dave Arnold, Liquid Intelligence

Clear filtered specialty coffee.

If this doesn’t bring a tear to your eye, I don’t know what will.
Credit: Dapper Coffee

Gel Clarification in the Kitchen

Over a decade ago, it became popular among European chefs (most notably Heston Blumenthal) to freeze meat stocks, and then thaw them over cheesecloth to create beautifully unclouded and rich-tasting consommé.

This process only worked, as it turned out, because meat stocks were extremely rich in gelatin. The protein from the gelatin forms an internal mesh within the frozen ice block (an extremely, extremely fine mesh—I’m talking of a molecular level here), essentially forming an internal 3D filter that never clogs. Brilliant, right?

Research & Development: Applying the Technique to Coffee

As gelatin is widely commercially available, it became fairly obvious to all of us at the Dapper Coffee R&D team that we might be able to replicate the process of the clarified consommé by simply adding gelatin to coffee—but we had… a few problems.

The freeze-thaw clarification process itself worked a treat, but we had completely overlooked one thing: gelatin turns back into jelly when it’s chilled. You can imagine our faces as we pulled the cold brew out from the fridge only to find bottles of coffee jelly.

Luckily, that was not the end of our coffee experimentations, because we managed to find a better and much cheaper alternative: agar agar.

Agar-Clarification

I’m not entirely sure why it never occurred to us to use agar agar in the first place. The properties of this simple gelling agent, which is derived from seaweed, are superior to gelatin in every aspect: agar turns into jelly faster, it leaks faster, and, best of all, the gelling process is irreversible (meaning the liquid that is clarified won’t turn into jelly as it sits in your fridge). 

On top of that, this method doesn’t strictly require you to freeze the liquid into a solid before thawing, it works just as well as a jelly.

Method

Just like with last week’s article on nitrous-free cold brew, at first it might be a little hard to wrap your head around the numbers and jargon. Trust me, though, the process is incredibly simple once you get the hang of it

1) Measure how much liquid you want to clarify (X ml). I usually do this process right after whipping up a batch of vacuum cold brew, and I use this method nearly exclusively for it.

Clear filtered specialty coffee.

Credit: Dapper Coffee

2)  Separate and reserve a quarter of the batch (X/4 ml).

Clear filtered specialty coffee.

Credit: Dapper Coffee

3) From the reserved batch (X/4ml), divide that amount by a hundred. Then, weigh out this new number in gram of agar-agar powder (X/400 g). Using a micron scale isn’t necessary, but it’s advisable.

scale

Credit: Dapper Coffee

4) Bring the reserved batch to the boil and scatter the agar-agar over it while whisking well to make sure it’s completely dissolved. Be careful: Agar-agar HAS to boil for at least 10 seconds if it’s to work. I recommend watching the pot come to a rolling boil and then humming two or three lines of a song before turning off the stove—I’m not joking.

pouring agar-agar

Credit: Dapper Coffee

Clear filtered specialty coffee.

Credit: Dapper Coffee

5) Add the ¾ of the original batch that you haven’t touched to the reserved batch. Take note: you ALWAYS have to add the cold liquid to the hot liquid to temper it. Agar gels incredibly fast, so if you add the hot into the cold, you might end up with goopy threads of jelly forming within the liquid—absolutely not what you want!

Clear filtered specialty coffee.

ALWAYS cold to hot. Credits: Dapper Coffee

6) Divide the coffee into containers of your choice and chuck them into the fridge/freezer to set. You can even use an ice bath if you’re as impatient as I am. Resist the urge to stir the jelly while it’s setting. This will prematurely break up the protein mesh.

storing clear filtered specialty coffee.

Credit: Dapper Coffee

7) Once completely set (and I mean completely), run a fork or a whisk through the jelly to break it into small curds (think scrambled eggs). This increases its surface area and helps it to leak quicker.

Clear filtered specialty coffee.

Credit: Dapper Coffee

8) Pour the jelly into a cloth bag. I use a plain one made of linen; I’ve found that cotton or linen works a lot better than cheesecloth (which is really more like a gauze) as the fibers are much finer. It’s also a whole lot cheaper than cheesecloth, and after a wash you can even reuse it.

Clear filtered specialty coffee.

Credit: Dapper Coffee

9) Lay the bag in a mesh strainer and let it drip into a container. DO NOT RUSH THIS PROCESS. Don’t poke it. Don’t squeeze it. In fact, don’t even look at it. Any form of agitation will make agar particles leak out of the cloth and you’ll end up with odd looking (though tasteless) floaters in your filtrate. You’d have to use the dreaded filter paper to get them back out.

creating clear filtered specialty coffee.

Credit: Dapper Coffee

Clear filtered specialty coffee creating process

Credit: Dapper Coffee

10) What’s left over in the bag is a jellied raft that has essentially captured all the oils and sediments from the coffee.

Clear filtered specialty coffee process

Not so nice.
Credit: Dapper Coffee

 11) And voilà! Enjoy your perfectly clarified coffee.

Clear filtered specialty coffee.

Heavenly! Credit: Dapper Coffee

Freeze-Thawing

At Dapper Coffee, we only have one grinder (which is already on its last legs), so grinding cold brew daily, and then tearing the grinder apart and re-calibrating it for espresso, just doesn’t work on an operational level.

For pure efficiency, we make large batches of the jellied cold brew and freeze them in measured quantities. Every morning, we simply pop a block out of the freezer and let it thaw so we get freshly clarified coffee every day!

Freeze-thawing also adds another interesting dimension to the process: the first bits that drip are incredibly concentrated and syrupy, while the last of it is super light in colour and watery. This is because the ice crystals that form in the freezing process melt the slowest.

Clear filtered specialty coffee.

Left beaker: Super concentrated first drips, Right beaker: Weaker and lighter last drips. Credit: Dapper Coffee

I usually mix everything together to homogenize it (for consistency), but separating the filtrate in stages make for some very interesting possibilities.

Give this method a go, and I promise you’ll never want to touch another piece of filter paper again.

Written by Christine Seah.

Perfect Daily Grind.

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