Can exposure to carbon dioxide spoil a lactic fermentation project?
I’m using lactic fermentation to make a batch of sauerkraut, fermented berries, etc. Rather than going the glass jar route I’ve placed everything in a vacuum sealed bag. This is a technique which Noma uses.
Over the next few days the contents will create a large balloon of carbon dioxide within the bag. Can the exposure to carbon dioxide spoil the contents, in the same way that exposure to air would?
Example image:
Would it be feasible to “burp” the bag, freeze the contents, vacuum, then allow to thaw to continue the ferment? This way I would be able to reseal the bag without worrying about the wet juices being sucked out by the vacuum sealer.
Best Answer
Great question!
Firstly, the build up of carbon dioxide should not jeopardize the ferment in any way. In fact, it probably serves to protect your ferment further from going bad or taking a turn in the wrong direction. Lactic acid bacteria grow under anaerobic conditions (absence of oxygen) during lacto-fermentation. These are the microbes that you really want to have thriving on the fruit or vegetable in the bag. As more carbon dioxide builds up in the bag, it further inhibits the growth of other competing aerobic microbes (that require oxygen to grow) such as mould that would spoil the ferment, encouraging lactic acid bacteria to prevail and dominate.
Secondly, you should not really have too much problems with running the vacuum sealer unless there is really a huge amount of liquid. You could pour out some of the excess liquid to reduce the level in the bag before resealing. You may also try sealing with a weaker suction.
I would strongly advise against freezing and then thawing the ferment. The freeze thaw process would affect the viability of the microbes and you would end up with a handicapped ferment as some proportion of the microbial population would die off as they are being frozen. You should only freeze your ferment for storage after it has reached your desired end state.
In fact, burping is probably not necessary if your ferment progresses fast enough to reach your desired end maturity. By then you would be concluding the ferment by cutting open the bag to harvest the contents.
Ultimately, I think the purpose of burping is simply to prevent the bag from bursting due to excess gas build-up.
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Quick Answer about "Can exposure to carbon dioxide spoil a lactic fermentation project?"
Firstly, the build up of carbon dioxide should not jeopardize the ferment in any way. In fact, it probably serves to protect your ferment further from going bad or taking a turn in the wrong direction. Lactic acid bacteria grow under anaerobic conditions (absence of oxygen) during lacto-fermentation.Which gas is responsible for fermentation?
More broadly, fermentation is the foaming that occurs during the manufacture of wine and beer, a process at least 10,000 years old. The frothing results from the evolution of carbon dioxide gas, though this was not recognized until the 17th century.Is lactic acid fermentation bad?
Safety and Side Effects. Fermented foods are considered safe for most people. However, some individuals may experience side effects. Due to the high probiotic content of fermented foods, the most common side effect is an initial and temporary increase in gas and bloating ( 32 ).Does fermentation cause food spoilage?
It's amazing that the three types of microorganisms that preserve food during the fermentation process can also cause spoilage. The good news is that it's fairly easy to keep food from spoiling by knowing which temperature and processing methods to use.Why does fermentation prevent food spoilage?
Fermentative bacteria, yeasts, and molds (the Good) preserve foods by producing metabolites such as lactic acid, acetic acid, propionic acid, ethanol, and bacteriocins that suppress the growth of spoilage microorganisms (the Ugly) and pathogenic microorganisms (the Bad) that are naturally present in foods.Lacto Fermented Blueberries // Noma Guide to Fermentation
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