posted by Dave Arnold
Upshot:
Anyone with a packet of agar and a whisk can clarify fragile fresh juices, or anything else for that matter, in under an hour with zero pieces of special equipment. The yield on the technique is high—as good as gelatin clarification. Read more for details.
Long Story:
Yesterday I wrote a post about a new clarification technique posted by Ideas in Food where agar gels are put in vacuum bags to get clarified liquids out of them. They call the technique “compression clarification.” I stayed up till 1am or so getting the post out, vegged for a bit, and tried to go to bed. I could not sleep. Something was gnawing at me. I kept thinking about how much harder the Ideas in Food block of agar looked in the bag as opposed to mine. Mine was so soft it broke just by moving it and was quite soupy in the bag. I used the same 2 grams of Telephone brand Agar per kilo of product that I always use, which is just barely gelled. I wondered why theirs looked so much harder.
Something else bothered me: I don’t like the term compression the way it is used by chefs. I don’t like it for the same reason I don’t like the Under Pressure title of Thomas Keller’s sous-vide book. The terms are misleading (unless Under Pressure is a pun on under-pressure, meaning less pressure than normal, in which case the title is hilarious). With the exception of items that contain air, foods in vacuum bags aren’t being compressed (except at the edge where the bag tries to press together). Instead, vacuum bags press against your food with exactly the same force that air was pressing against it before. Only if your food has a lot of air holes that get evacuated during the vacuum cycle will it feel a lot of pressure. Air holes will feel a force of about 15 psi because you have removed that much pressure from them, sealed them inside the bag and then brought the force of the atmosphere back to bear on them. Even flash infusion isn’t compression, it is injection. Many things with air in them, a block of aluminum foam for example, won’t compress in a vacuum bag either (although it will be under compression), because they are too strong.
Agar gels, if well made, don’t have air. They are essentially liquids with some solids mixed in, and are uncompressible.
Also, I had been using physical techniques to clarify with agar for quite some time: see my experiments with spin gel clarification. Something I had forgotten was that I could get clarified juice out of those gels even after they were broken. I had dumped out one of the gels and spun it again, and even though the gel had been broken, I got more clarified juice. The reason I didn’t develop that technique further was it required a centrifuge.
All of a sudden it hit me like a ton of bricks: not only do you not need the centrifuge, you don’t need the bag and you don’t need the vacuum. All the bag was doing was slapping the agar silly. I could do that with a whisk! It was 3am. I jumped out of bed trying not to wake my wife, got dressed, jumped on my bike and dashed off to The FCI to get agar, OJ, and cheesecloth. I wanted lime juice, but at 0 dark 30 in the morning I didn’t want to squeeze any limes. OJ was fine.
Well, it worked like a champ. I made it home bout 3:45, clarified the juice, shot the pictures, and was in bed by 5. I slept like a baby—till 7 when I had to get up with the kids.
The advantages of this technique are:
- It is fast so fragile juices like lime can be clarified
- You need no special equipment
- It is vegetarian
- It is foolproof
- The results are clearer than gelatin for some products
- You don’t tie up fridge space with hotel pans
- You don’t tie up freezer space with hotel pans
- Yield is high
- Because there’s no freezing involved, you can clarify alcohol without liquid nitrogen (I’m letting the cat out of the bag—that was supposed to be my next post)
Caveats:
- Agar needs to boil to hydrate. Don’t boil heat-sensitive juices like lime. Instead use 4 parts room temp (25°C) juice and hydrate in 1 part water. After the juice is added to the boiling agar-water mix (off the heat) the temperature will be perfect. If you are using refrigerated juice that can tolerate some heat, boil 1 part liquid with the agar and add in 2 parts refrigerated juice.
- Use real cheesecloth. Don’t use the stuff from the supermarket with the picture of the turkey on the package. That stuff is ludicrous. I don’t know why they make it. If you can’t get real cheesecloth use muslin, a large cloth napkin, or a smooth-finished dish towel.
Instructions
1.) Measure out 500 grams cold OJ, 250 grams cold OJ, and 1.5 grams of Telephone brand Agar (0.2% of total juice weight). 2.) Whisk the agar into the 250 grams of cold juice to disperse the agar then heat to a boil while stirring and allow to simmer a couple of minutes to hydrate the agar. 3.) While briskly whisking the boiling-hot agar solution add the 500 grams of cold juice in a thin stream. Don’t allow the mix to drop below 35°C or pre-gelling could ruin your result. 4.) Put on an ice bath to set.
5.) Using a whisk, gently break up and stir the gel into agar “curds.†6.) Dump the curds into a cheesecloth lined chinois. 7.) Lift and gently squeeze to drain. 8.) After a while you can dump the curds back into the bowl to break them up some more.
9.) Alternatively, you can just stir the curds in the cheesecloth to release more juice. 10.) Twisting the cloth presses juice out gently and quickly. Don’t twist too hard or you will extrude the agar through the cheesecloth. 11.) The clarified juice. 516.8 grams! And I started with unstrained juice! If there are any agar particles in the juice, filter it through a coffee filter. 12.) The leftovers. 87.7 grams. Yeah I know the numbers don’t add up to 750 grams.
That’s it.
Dave,
Very nice.
Thanks Alex,
And a very nice to you too. Thanks for getting this ball rolling.
oh yeah, and our block of agar in the vacuum bag was wrapped in cheesecloth, hence its solid appearance.
A
amazing!! simply amazing! I am into making a “modern greek salad” and wanted to have a clear tomato foam to accompany the dish. Given that I do not have a vacuum sealer, nor a centrifuge I think this method could work! many many thanks again!
Awesome,don’t really need to say much more
JESUS H. TAPDANCING CHRIST CAN THIS DAY GET ANY BETTER???
This is just ridiculous. I love it. Yesterday I was reading Alex’s post on Ideas in Food in complete amazement and the very next day I’m reading this one in exactly the same way. It’s like watching a really good tennis match. Once the ball is in the air, it’s hard to keep up with it.
this is amazing, I can think of 1000 uses for clarified lime juice and here it is how to do it foolproof!… thanks guys!
This is perfect for me, since, despite having two refridgerators and two freezers at my disposal, I never have space in them for hotel pans! Awesome.
Would using a Superbag work?
I think it would. In fact, I know it would. But to quote my next post: A word to the wise: I think superbags might be paint strainers in disguise. http://www.thecarycompany.com/containers/ez-strainers.html
You’re saying that I paid $35 for a 1 L (0.26 gallon) Superbag when I could have paid $11.61 for a 5 gallon one (nineteen times larger)?
I think you may be right. The only comforting thing I could think of is that they don’t sell paint strainers in small sizes. I don’t need to filter 55 gallons of solution. Please correct me if I am wrong.
What confuses me is why did the person who invented cold gel filtration to begin with (McGee?) decide to add the “cold” part (as in freezer). This solution seems more logical to me, as in a more natural progression in thought as opposed to “let’s freeze this block”
The initial gel clarifications were done with gelatin. Gelatin won’t work with this technique (I’ve tried). Freezing and thawing was the only way to do it. Agar was a relatively recent clarification choice because it is vegetarian and doesn’t melt at room temp. No one thought to not freeze it. Funny, right?
And now, a reason NOT to get the Vacuum sealer… heh… Awesome technique!
So RAD!
This is the post I’ve been waiting for. Thanks so much. Awesome.
I’m not sure about agar, but I think gelatin is acid sensitive. Is it possible that some of your original trouble with the lime/agar approach is acid hydrolysis of the agar?
Hi Jeremy, We’ve never had any trouble being able to physically clarify lime juice. It just tastes bad becasue it has been sitting around too long. For me, lime juice isn’t good even the next morning after its juiced.
Bravo!
from everyone who has witnessed agar syneresis but never put 2+2 together.
This is amazing… for my first try I did watermelon juice, and it was less than an hour from cutting melon to drinking sparkling clear liquid. Really opens the door to doing clarification on a regular basis.
One small tip, probably obvious but I didn’t realize it at first – it is wise to give your juice an initial straining through a fine sieve or chinois before gelling – no reason to tie up agar or cheesecloth with a bunch of pulp that you can trivially remove.
Good point Michael. I forgot to even mention it because straining is SOP here. Just a habit. In fact, was weird about this post was that I forgot to strain the juice (I was tired).
Oh, and one more thing… I find it easier / more thorough to hydrate agar with an immersion blender instead of a whisk, and you can use it to combine the agar with the unadulterated juice as well.
I think that is fantastic because first its pure vegetarian. The time issue is perfect you don’t need a whole day. At the hotel we do shots of Clear juice as a special amenity but to get a good yield take a too long . Thanks for the ideas.
One of the things I always hated with the gelatin freeze/thaw consommes I made was the lack of body (unless gelatin was added back)
Since agar melts at a higher temp than it gels can’t it be first gelled and then warmed so any gelatin in say a chicken consomme would be allowed to melt and pass through while the agar held the impurities?
Hi Joel,
That is an interesting question. I wonder whether the agar would hold on to the liquified gelatin. If you try it will you tell us the results? We have always told people to add gelatin back to stocks after clarification to restore body. One note. We have tried on several occasions to add agar to extremely concentrated stocks that we had treated with enzymes to break the gelatin (both corolase and regular meat tenderizer). We were trying to make a meat glace fluid gel. The results were always miserable. Something about the way the agar reacted with the hydrolyzed gelatin created a gritty, sandy, unpleasant texture. Clearly agar and gelatin talk to each other, but I don’t know what they are saying.
Truly, truly nice and not a lab tool in sight…
I know it! Finally something you could even do while camping in the woods.
Oh and BTW Dave kudos to you for really sharing exactly how you do this stuff, this is in marked contrast to some in the field, and it really helps everyone move cuisine forward.
Thanks Joesan. We appreciate the kind words.
I know this is off topic but I thought you should know and couldn’t comment on the older post.
I finally got together with “cookiejesus” yesterday at a wine tasting and pretty much all the Aquavit was gone after about 30 mins… Good stuff… You can see the photos on the link on my name.
Cheers!
Awesome!
Dave A
Without a proper kit (gram scale, good thermometer) I did my best on this one.
Essentially I followed the instructions for the agar filtration only I warmed the bowl, after setting, in a warm water bath. Knowing that the agar would melt out at 80-90 c I wasn’t worried about it melting in the warm water. I then attempted to filter through cheesecloth and at first I thought it was a bust-as it seemed to lack body-but as I was about to throw it out I noticed my hands were sticky (Gelatin?) so I reduced the liquid by half and sure enough it had the body of a rich glace. I think I would try a warmer water bath next time to see if it would produce a better gelatine yeild.
At any rate there could be something there.
I tried out this exact recipe today, for fun and it worked out great. (and made a great late night screwdriver)
I just got a vacuum chamber for my studio, and when its just sitting around now ill try Vacuum infusing clarified juices into random foods.
thanks for breaking down such a great technique with wonderful instructions so easy even a home cook like me can do it during late night experiments.
I’ve been thinking about ways to squeeze as much juice as possible out of a larger quantity of gel. Squeezing the cheesecloth in a benchtop cider press might be worth trying.
I think at some point the more you squeeze the more you expand the fibres of the cheesecloth and the gel mixtures extrude through the cloth.
The other thing that i found that really bugs me is the yield. I might have been doing mine wrong but out of a 700 g plus i managed to probably pull off about 300 g plus before the agar started seeping through. I also did replace the cloth just to be sure. I tried single and double layered too.
I’ve been using the freeze thaw method for awhile now and have found that if you allow the initial “coloured” ice to defrost and collect the “clearer” ice before it is completely defrost (reserve that for another batch if you want to be calculative) you have a pleasant tasting juice.
Just tried it with frozen papaya, tres tres tasty, probably be using it for a dip.
Hi Darren,
You should be able to get much higher yields than that. We use a technique called “massaging the sack.” The idea is to clear the surface right by the drain holes in the cheesecloth. Remember to strain over a coffee filter to catch expressed agar.
Trying this out today. Hopefully I can put it together correctly.
Just to let you know. I’m a lowly home cook, and I tried this technique and it worked fantastically. I was making a large bunch of mojitos for my partner’s birthday pre-going-out gathering, and I wanted to put it all in a large glass dispenser, but I didn’t want it to be clouded especially as I was using essential spearmint oil along with the simple syrup (thanks Scott Beattie!). I thought the whole technique was really easy except for pulling out that jewelry/drug dealer scale to measure out the .2% of agar agar. Didn’t weight the final outcome, but started with 1kg of lime juice and still had about a liter left. Also could kind of feel the agar coming through the muslin when massaging the sack so was an easy indication to stop and break the curds back up again. Wish I had put down a coffee filter though as at one point I didn’t get the corners lined up well on the muslin when lifting it up from the chinois and had a bit come out of the sides. That added a little bit of impurities (RATS) but the technique itself worked great and on the whole it still looked almost completely transparent.
Fantastic. Thanks for the feedback. Home cooks aren’t lowly.
“The only comforting thing I could think of is that they don’t sell paint strainers in small sizes. I don’t need to filter 55 gallons of solution. Please correct me if I am wrong.”
Not trying to give you buyer’s remorse, but the superbag may actually be an industrial filter of the type sold at this place:
http://www.mcmaster.com/#catalog/115/378/=4pckpx
Prices are in the $6 to $9 range. You can get them in nylon, polyester, or polypro … I’m not sure what the Superbag uses or what’s best.
I’ve been buying similar ones to these in all the materials from an ebay seller (who offers free shipping) and am trying out the concept. For the price of one Superbag I’ve been able to get several, in mesh sizes from 55 microns to 250.
I can so far report that they’re easy to use and surprisingly easy to clean … easier than a chinois, anyhow. But even the 100 micron size doesn’t really clarify stock. I’m waiting to try the 55. There’s a 25 micron version available if that doesn’t work.
@Paul R – Can you tell me the name of the email seller?
Sorry, I meant ebay seller
have you tried simply adding pectinase enzyme to orange juice? when i make wine this works perfectly to clarifying freshly pressed cloudy grape juice. Simply mix and refrigerate and you get crystal clear juice and compact solids at the bottom of the vessel after a couple of hours. It should work on oj but anything with a really low pH like lemon and lime might not. Certainly apple, cranberry and i’m sure many others would.
Hi Anthony,
It works with orange juice but not with lemon or lime.
Dave, this is a very late post but I have only just found your blog! I love this technique and I have been using it to create some cool cocktails latley… When are you going to tell us how to take the colour out of alcohol? I am dying to know cheers
Hayds
Ahh. Good question Hayds,
The only way I know (other than Carbon filtration which also strips flavor) is through re-distillation. I’ll look into it though.
How long does the clarified juice, (in the case of lime, which seems so fragile to me), last before the flavor quality begins to degrade?
Hi Ian,
Lime juice doesn’t last any longer after it is clarified. It must be used on the day it is made.
Dave,
I recently tried to clarify a very cloudy stock, mainly flavored with brown milk solids, with agar. The results were not very good. I must have gone wrong somewhere along the line, the problem is that every step seemed to go exactly as you described and I don’t know what I would do differently next time. A detailed documentation of what I did can be found here(http://ijustcook.blogspot.com/2010/03/brown-butter-consomme-pt2-clarification.html). I am going to try again, but if there was something glaring that I missing I would very much appreciate your advice, if not thanks anyway, Cooking Issues is fantastic!
Adam S. I’m in Ireland right now and my Internet is spotty. I’ll look at your detailed post when I get back. Does your stock have natural gelatin in it? That could be a problem. In that case you should do freeze-thaw clarification.
I know this is an old post but I think I may know the reason why agar clarification doesn’t work with cloudy stocks and it’s not an interference between the agar + the gelatin but more because by not defrosting in the fridge the fat in the stock doesn’t stay solidified and some of it leaks into the final consomme. I did a few experiments and detailed the results here if you’re interested:
http://foodblog.stefanovozza.com/?p=77
Thanks Stef.
Dave,
I tried to clarify a chicken/lamb stock over the weekend using your method – jelly set fine, and I let it drip through at room temperature without squeezing after whisking. It worked up to a point, but wasn’t crystal clear a la gelatin freeze-thaw clarification. Also, the resultant liquid retained some gelatin as it set when put in the fridge following clarification.
I’ve seen from a couple of comments that you mention that if the liquid to clarify with agar has gelatin in it, then it may not work. Any idea why this may be?
Second question – can the gelatin clarification method work without a freeze thaw i.e. can you break a fridge set stock with a whisk and collect the liquid as for the agar method?
Thanks
Ian
Hi Ian,
I have noticed funky things happening with agar gelatin systems. If you break down the gelatin in a stock using an enzyme (corolase, papain, etc), then reduce the stock and make an agar fluid gel out of it, it takes on an unpleasant, grainy texture. I don’t know why. I would recommend standard freeze-thaw on gelatin containing stocks. As a side note, we have done a lot of work on hyper reducing freeze-thaw gelatin stocks (they stay liquid even after they have been preposterously concentrated and won’t glue your mouth together like over-reduce stock can). We haven’t added agar to one of those stocks.
Gelatin cannot be use like agar for quick clarification –it doesn’t weep liquid the same way and isn’t as brittle. At least I haven’t had luck.
Does marinating fish in clarified lime juice (by any technique) result in a difference compared with regular lime juice? I’d try myself but am currently on the road.
Keep up the good work.
Hi Carey,
I doubt clarification would make a difference in a marinade.
I just tried this on a mushroom broth, but result is cloudy, a few minutes later particles clumped together, will tweet the pic. Probably it was the coffee filter I used.
Would be possible to use 50 grams of juice to boil to hydrate the agar instead 250 grams ? The taste would be better.
It is difficult to hydrate agar in small amounts of liquid because of scorching/mixing/evaporation problems. Also, if you use a very small amount of liquid to hydrate, you have to make sure that the liquid you temper back into doesn’t drop too low in temperature. Unlike gelatin, agar sets very quickly once it drops below its gelation temperature.
Hi,
via “Ideas in food”, I stumbled across your detailed explanation about clarification, and had to try it out immediately. It worked liked a charm – half of the time:
Orange juice and zucchini soup yielded great results, while soy sauce and coffee didn’t work at all, the “clarified” fluid looked just like the original one. Guessing that it had nothing to do with the color ;-), I wonder whether there is any explanation, or hint of which kind of substances are out of question. Or was it just bad luck, and a strange coincidence?
Thanks in advance for any input.
And, most of all, thanks for your great website.
Howdy Kai,
I’ve never tried soy or coffee. Wonder why they didn’t work.