4 methods for clarifying stock

What if I told you there’s a way to get stock so crystal clear you can see a coin in the bottom of a 15 liter stock pot? And is so easy to do it’s just fucking infuriating? Without loss of flavour? Here are four great and versatile ways of clarifying your stock that everybody ought to know.

The reason why you would want to clarify a stock is mostly a matter of appearance – in fact, filtering sometimes reduces the flavor intensity. But a crystal clear consommé or wonton soup can be extremely impressive and satisfying:

Stock vs broth?
Simply put, broth does not have any bones in it, while a stock does.

Stock gets its flavor, body and mouthfeel from simmering bones along with aromatic vegetables and herbs to break down the collagen into gelatin. Collagen is found in the connective tissues and cartilage, and the more collagen, the more flavor. Which is why I always prefer using oxtails for my beef stock.

Breaking down the collagen takes time and temperature. Collagen starts to liquify at around 70C, but it takes a very, very long time to break it completely down into gelatine at this temp. Ramp up the temperature to a gentle simmer, and it still takes 3 hours to fully gelatinize the collagen in oxtails.

A broth on the other hand gets its flavor from simmering vegetables and meat, but no bones. As such, it lacks the richness a stock has, due to the lack of gelatine. Technically, there is no such thing as a vegetable stock either, since it has no bones in it. And since there are no bones or collagen to break down, it’s done simmering in 20-40 minutes.

To skim or not to skim the scum
What is the scum anyway? The white foam that floats to the surface of a stock is simply protein. Skimming it will improve clarity, but not by much at all, so I rarely bother with the 20 minutes it takes. You’re still left with a fairly murky stock no matter how much you skim:

Depending on how clear you need it, here are your options:

  • Rustic stew or gravy: drain through a fine sieve.
  • Rustic soup or jus: drain through a fine sieve with 4 layers of wet muslin cloth.
  • Clear soup or jus: drain through a fine sieve with 4 layers of wet muslin cloth, then egg raft it.
  • Crystal clear soup or consommé: drain through fine sieve, then ice filter it.

Technique 1: Muslin cloth
The simplest way of clarifying a stock is to simply pass is through layers of wet cheese/muslin cloth. Simply wet your muslin and fold into 4 layers in a colander or sieve and pass your stock or broth through this.

Technique 2: Egg rafting
Egg rafting is a very quick, very easy, and very traditional way of clarifying a stock or broth. It will give you a very, very clear stock, but you will also lose a bit of flavor in the process. It is a great option if you’re in a bit of a hurry, and can also be used for vegetarian “stocks” as well, such as the vegetarian Promite stock.

Take your stock, heat it gently up to around 50C, then add one whipped eggwhite per liter (save the yolk for pasta carbonara or something) as well as the crushed shell to the pot, stirring it quickly into the stock. Quit stirring.

As the temperature climbs past 60C, the egg whites start to coagulate and the proteins and impurities in the stock start rising to the surface, trapped together with the now brown and nasty gunky egg whites.

Continue heating to a gentle simmer. Some say simmer for 5 mins, I say I see no difference at all. So I simply stop there, and pass it all through a wet muslin cloth, and I’m left with a very clear and elegant stock.

Technique 3: Ice filtration (or gelatin clarification)
This is the ultimate “fuck me this stock is clear!”. And it’s so easy it’s infuriating. And you have no loss of flavor.

You start out with a stock that’s been passed through a fine sieve to get rid of the worst solids. Put this stock in a lidded container and freeze it. (or ice cube tray so you can take out exactly as much stock you need)

Once frozen, prepare a fine sieve on top of a bowl. Take the frozen stock out of the freezer, dump it into the sieve, put everything into your fridge, and wait.

What happens is that as the stock is thawing, the water will thaw, but the gelatin stays solid, and the gelatin will then retain all the impurities from the stock. You’re left with a wobbly blob of gelatin that looks absolutely disgusting (and which you discard) – and a mindblowingly clear stock.

This stock is devoid of gelatin, so I often add back some gelatin powder to give it some of that silky rich mouthfeel that gelatine gives you.

Technique 4: Agar filtration
While gelatin filtration is fantastic, it is hardly vegan, nor is it vegetarian. Agar agar is a gelling agent made from seaweed, and is fully vegan. Agar clarification is a little bit trickier and labor intensive than gelatine filtering in that you have to carefully weigh the amount of agar to liquid to clarify. But you get near instant results, on par with egg rafting.

Weigh out the amount of stock you want to clarify.
Calculate how much agar to use (0.2%): 0.002 X StockWeight = AgarWeight

Let’s say you have 1 liter stock you want to clarify. 1 liter stock is very close to 1000g:

0.002 X StockWeight = AgarWeight
0.002 X 1000g = 2g agar

Measure 300g stock into a 2 liter pot, add 2g agar, and bring to a simmer while stirring. Continue to simmer for a few minutes to let the agar fully rehydrate.

While stirring continuously, add the remaining 700g stock in a thin stream into the pot. Do not allow the temperature of the mix to drop below 35C or pre-gelling could ruin the result.

When the stock is fully incorporated with the agar mixture, put in an ice bath to set. When set, use a whisk to break up the agar, creating “curds”. Dump these curs into a sieve lined with a fine cheesecloth/muslin.

Squeeze to drain, then stir the curds some more, squeeze and repeat. Squeezing or twisting too hard can make the agar extrude through the musling, so don’t be too forceful.

And there you have it! Four great ways of clarifying your stock added to your culinary repertoire 🙂

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