Under (Negative) Pressure – Flash Pickling

When David Bowie sang Under Pressure with Queen, I’m fairly sure he wasn’t thinking of negative pressure, but that’s exactly what I’m talking about today.

I was reading Cooking for Geeks, lent to me by the good Dr. D. Gustibus, and I came upon a small section on Flash Pickling. Flash pickling is, well, pickling in a flash! The principle is simple, if you suck out all the air from the tiny spaces in your food, when you release the vacuum, the voids will be filled by pickling juices rushing in as the food re-expands back to its (near) original state, and you’ll have an instant pickled whatever. Well, the concept is slightly flawed, as real pickling uses the principle of osmosis to actually replace some of the fluid within the cells of your food, not just soak the cells in fluid.  However, after flash pickling, if left to sit for a while, true pickling would occur (in a much shorter time that normal pickling would take).  But I digress…

Traditional pickling is done with either a lengthy sit in pickling juice (a.k.a. brine) or cooking in brine.  Strawberry jam is really nothing more than strawberries pickled in sugar using heat, and then mashed.  The problem with these methods of pickling are that a) we don’t have the time to wait the days or weeks it takes to cold pickle something or b) we want to preserve the texture of our food by not cooking it.  Flash pickling allows us to avoid both these pitfalls of traditional picking, while still producing something that highly resembles a pickle.

The book suggests using a consumer vacuum sealer, most commonly used for vacuum packing things for the freezer.  Most come with an accessory vacuum jar, for extending the life of some fruit or vegetables in the fridge, that works perfectly for flash pickling.  I decided to try a quick pickled salad of tomatoes, cucumbers, and strawberries in a light vinaigrette brine.

The rigid walls of the jar allow you to obtain a much much higher level of vacuum when compared to the normal bags used by the machines.  Even still, I wasn’t impressed with the amount of vacuum my unit was pulling.  I could see some tiny bubbles coming out of the mixture, but it wasn’t very impressive.  I wanted more.

Fortunately, I just happen to have a small lab compressor/vacuum pump I bought from ebay for about $80.  Not knowing how much vacuum the jar could handle, I decided to take some precautions in case of a catastrophic failure by putting the vacuum container in a large stainless steel bowel.  Given that the worst that would happen was an implosion, I knew I was safe, but I really didn’t want to have to clean up a jar of pickled salad after it spilled out all over the kitchen.  Luckily, the jar held up nicely, with only minor inflection of the sides and bottom.

Positive pressure in on the left (yellow hose) and negative pressure in on the right (hooked into the jar).

Now we’re getting somewhere!  Lots of bubbles expanding and coming to the top of the brine with the higher vacuum.  As you can see, my little pump is able to pull about 24 in. Hg vac (or “Inches of mercury vacuum”), much more than the other unit could.

And the results? Well, pretty good! Certainly opens the door to much experimenting. What I enjoyed most was the retention of the original textures while still being incredibly flavourful.  Also, having removed all the air, the colours become more vivid looking and more translucent, making for a rather aesthetically pleasing salad.

Flash pickling: a definet win.  Very easy and impressive results.  Next, I want to try pickling pear slices in crème de cacao white for after dinner.

So have some fun, and try it out for yourself! Experiment and see what happens, and let me know if you’ve had any great successes (or failures)…just remember that when you’re using things like lab equipment, not designed for the consumer or the kitchen, you have to be extra careful.  I don’t want any of my readers getting hurt (I don’t have enough to spare!).


Bon Appetite,
Mr. Carnegie, Scavenger Gourmet

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