How to Get the Air Out: Spinning Aggressive: Centrifuge

Another method to https://www.chefsteps.com/activities/how-to-get-the-air-out

Though its practical relevance is, well, debatable, as I suspect there are a lot less centrifuges out there than vacuum chambers, I find some of its benefits quite appealing compared to the other methods. It can also be considered as another use case trying to justify owning a centrifuge...

Centrifuges separate components of a liquid mixture based on their density and particle size.

Air has a very low density, thus the difference between its density and the average density of the liquid mixture is usually a lot larger than the difference between the densities of the mixture's components. Furthermore, the size of air bubbles is usually a lot larger than the particle size of the mixture's components.

This means that a centrifuge can force air bubbles to the surface before the mixture's components start to separate. I found that already a moderate speed of 1000-1500RPM for 1-2 minutes tends to be enough to bring all bubbles to the surface in mixtures where they would never rise otherwise (e.g. thicker fluid gels). The bubbles don't pop, but form a foam on top that can be simply scraped off or blowtorched into oblivion.

At these speeds the forces are not yet that strong, so no need for special centrifuge bottles. Their narrower opening would presumably make removing the foam a pain anyway. I usually spin and store in the same round plastic storage containers, sparing the transfer from one container to the other. I even tried it with standard twist-off jars, worked great, though that's not something I would recommend.

Pros:

no splatter (I presume the popping bubbles in a chamber vac cause some splatter; never had he chance to try),
no risk of overflow, because the mixture doesn't expand,
can spin directly in storage containers, if rotor allows, i.e. in swing-out buckets,
bigger batches, depending on rotor capacity,
doesn't need a chamber vac

Cons:

bubbles don't pop, but form a foam "crust" that have to be removed (scraped or torched),
must balance containers,
needs a centrifuge

Find more posts tagged with

Recipes Q's

Comments

Theo_129732

What type of centrifuge are you using? Are you using bucket adapters for your glass jars? Is it a tight fit, or is there play? Have you broken a jar yet?

szeder_185682

I use a Jouan C312 with the 4 round swing-out buckets rotor.

I don't have any bucket adapers, because they're are made to fit centrifuge bottles (or vials which are even smaller), and I have serious aversion against bottles with narrow openings. In fact, I firmly believe that the widest point of any container intended to be filled with anything more viscous than water must be its opening, especially when it's intended to be filled and emptied frequently

There is plenty of play around the jar in the bucket, but there has to be, because the bottom of the bucket is not completely flat but somewhat \___/ shaped, and a jar has to fit into the flat part. The room around the jar doesn't seem to matter, however, because the centrifuge doesn't start or stop so abruptly to make the jar move around in the bucket, and pretty soon the centrifugal force "glues" the jar in place anyway.

I'd like to point out that I only tried a pair of European (German?) jars; Germans here call them "Twist-Off Sturzgläser" (although twist-off doesn't quite sound like German, does it). Apparently these jars are mightier than the puny typical American mason jars, as noone here seems to care about "fingertip tight" or "loosen by a quarter turn". In fact, even if they wanted to, they couldn't, because these jars have less than a quarter turn between completely open and fully tightened. So either these jars are indeed stronger, or the locals here are ignorant and/or lucky. Or, perhaps, Americans are way too careful, after all they don't allow French cheese or Kinder Surprise, either

I haven't broken any of these jars yet, but I have only tried it once, so this doesn't really say anything... and it's unlikely I'll ever do it again. Though I wonder, whether the forces during such a low-speed de-bubbling centrifugation might actually be smaller than the forces a jar must whitstand resulting from the pressure differences during cooking or after cooled down.

Theo_129732

Thanks for the info. I totally agree that the opening of a jar should be the widest part. Also, any jar that I can't get my hand into for cleaning goes right into the glass recycle bin.

lfmichaud

Using a Beckman TJ-6 at about 3000g with swinging buckets and it work good. I personally wouldn't use glass in a centrifuge to minimize the amount of sharpnel when rotor will fail... I personally found that ziploc containers fit perfectly once you grind the lid off. They will fail at some point after dozens of run but they are safe and cheap to replace.

szeder_185682

I'm opposed to glass jars mainly because glass is inherently rigid and brittle, and presumably would shatter right away when the forces become too stong, while plastic containers can first bulge and deform quite a bit.

I don't know what would happen, if a jar, or any container for that matter, were to fail during centrifuging. On one hand, the rotor would still rotate, forcing the shrapnel and the content to stay in the bucket. On the other hand the whole thing would become off-balance, and could perhaps shake bits and pieces out of the bucket. I don't know which factor is stronger.