Fermenting food for probiotics using chamber vacuum sealer?

[Derek Tran]

As one of those long term ketogenic dieters, I want to start experimenting with food fermentation and decided to try out this recipe for kimchi https://simplyafoodblog.wordpress.com/2013/07/03/low-carb-fermented-food-korean-kimchi/I have a VacMaster VP215 chamber vacuum sealer that I use for a lot of sous viding.

 

This is my first foray into fermentation but from what I hear, the goal is to keep oxygen out of the mix during the fermentation process. I don't have any jars or appropriate pickling containers, so thought the chamber vacuum sealer might be a good option. Is this a good idea and advantageous over other container/jarring methods? I'm not to keen on the science of fermentation (yet) but am intrigued by the idea of creating delicious foods with beneficial probiotics and all that.

 

Also, for keeping the probiotics alive while heating, what is the best method? I know high heat kills probiotics but if I wanted to add it to a stir fry for example, perhaps just mixing room temperature kimchi with the stir fry ingredients once they are removed from the pan would keep the probiotics alive while warming up the kimchi?

 

Cheers!

[Smithy]

It's true that lactobacillus fermentation is an anaerobic process; however, it isn't necessary to provide a totally air-free environment in the fermentation vessel. You just have to keep the stuff fully submerged in brine of the right concentration. You may find this article enlightening: Aerobic vs Anaerobic Fermentation Controversy in Sandor Katz's "Wild Fermentation" blog. Among other things, he says:

"...lactic acid bacteria...do not require oxygen, but are not inhibited by its presence; in contrast, certain other bacteria (for example Clostridium botulinum) ... require a perfectly anaerobic environment."

Unless kimchi is very different from kraut or cucumber pickles, I'd be leery of starting the fermentation in something where I couldn't periodically check the progress and make sure it's fermenting.

I have no insight for you on the heat issue, however.

[Derek Tran]

Thanks! Would you say theres anything wrong with using a vacuum sealer/bag even if a totally air free environment isn't necessary? Only because I don't have any other appropriate and big enough containers to do the fermentation in. What time of periodic checking do you have to do on the fermentation?

[Smithy]

I'm a novice at fermentation, so most of my knowledge comes from books rather than experience...I hope more experienced people will chime in here.  With my batches of sauerkraut I've kept an eye on the liquid level (make sure it stays covered), the odor, and the color / visible texture of the cabbage  to see whether it was starting to soften and change color after about a week.  The 'sniff test' happens every few days for me.  With a clear glass jar I've been able to look see what's going on in terms of color and texture change; with an opaque crock I've had to use a clean spoon to lift the lid and poke down into the cabbage to see what's doing.  Whether I *have* to do that so often is another question.  After about 2 weeks I start to taste.  The only part of these 'tests' that would require you to break the seal would be the smelling and the tasting.

 

The larger issue, to me, seems to be the need to allow gases to escape.  During active fermentation the bacteria are generating acid and carbon dioxide.  If you vacuum seal your container, would you be leaving some head space so the gases could accumulate?  I'm told that ferment explosions are, er, unpleasant.  

[pbear]

I've done a fair amount of kimchi.  I'm pretty sure a sealed bag would be a mistake.  For the linked recipe, a vented zip-top bag should work just fine.  My advice, though, would be to use a recipe where the cabbage is cut up and get a few canning jars.

[cyalexa]

I have one of the original Rival Crockpots and my Corelle bread and butter plate fits inside nicely. While I have been coveting an actual fermentation crock I must say my cobbled together system works very well. 

[Martin Fisher]

It's not a good idea....questions of safety aside...using a chamber sealer for natural fermentation leads to bad texture.

 

+1 on the canning jars.

If you're in the USofA, any good hardware store and the like should have 1/2 gallon canning jars....they're great for fermenting.

[Franci]

If you are looking for an easy kimchi recipe to start with, I highly recommend Holly's recipe. I really like it

http://www.beyondkimchee.com/easy-cabbage-kimchi/

[_john]

If you suck a hard vacuum it does change the texture as diggingdogfarm said. That being said I use a chamber vacuum sealer to ferment things that have air pockets in them, like stems of turnips, to assure good brine penetration. I back slop from a previous batch to make sure the lactic fermentation beings quickly. After your sealed bag puffs up like a balloon you know that the fermentation is going nicely. It is totally sealed so if you let the bag become taught with carbon dioxide and the bag is strong you can get mildly carbonated fizzy pickles.

[btbyrd]

Apart from texture issues, I don't think there's anything "wrong" with sous vide fermentation. Dave Arnold at Cooking Issues has mentioned this technique a few times (though he hasn't really discussed it in depth) and seems to think it's worth trying. His only real caution was that once fermentation gets going, there's going to be a lot of CO2 produced and the bag will puff up. If it really gets going, the bag may explode. So he suggested that you double bag it, using a smaller bag to contain the food you're going to ferment and sealing that in a bag the next size up.

 

Over at Star Chefs, there's a profile of chef Sanghoon Degeimbre that outlines his method of preparing kimchi sous vide. It's not a "recipe" per se, but it's proof of concept. He uses a centerfuge, on the cabbage juice but that's not really necessary. The folks over at Nordic Food Lab have also mentioned SV fermentation before, suggesting that you basically just toss vegetables in 1-1.5% of their weight in salt, seal, and let it ride. I can't find the specific post on their site, but in a post on the microbiology of fermentation the lead image is of a puffy vacuum bag. If Noma's doing it, it's probably worth trying. I just sealed some napa cabbage with some salt following this program and will report back on the results. (I didn't have the time to go "full kimchi" on it at the moment).

 

But if the OP is seriously interested in trying his hand at fermentation, there's not really a need to invest in an expensive, unitasking fermentation crock (although they're nice if you've got the money and the space). For thirty or forty bucks, you can pick up some wide mouth mason jars and some special lids that will vent excess gas (Pickle-Pro and Kraut Kaps are two quality brands) and you'll be able to ferment to your heart's content.

 

Also, if you're looking for good information about fermentation, I can't recommend Sandor Katz's two books ("Wild Fermentation" and "The Art of Fermentation") highly enough. The first is more recipe driven, while the latter is more about the theory behind fermenting different types of food. His website also has a lot of quality information.

[btbyrd]

In this podcast from Nordic Food Lab, they suggest that you don't pull a hard vacuum when fermenting in the bag but instead leave a tiny bit of air in there to keep botulism from growing. If you have a chamber vac that can save settings, you might consider adding a fermentation preset.