Fermentation history and scienceColumns Food & Drink 

Fermentation: A Brief History and a Little Science

By Tom Andersen

A Brief History

By many accounts, fermentation was “discovered” about 12,000 years ago with the natural fermentation of dairy products in the sweltering heat of North Africa. A few thousand years later, the Chinese were fermenting rice and honey and in a couple thousand more years, Egyptians were turning out some fine loaves of sourdough bread and beer. I wonder what the hieroglyphics would look like if they had known that 5,000 years later individually baked loaves of sourdough bread would be considered “artisanal” rather than just food? Along the way, these ancient cultures recognized that this “old” food wasn’t killing people and clearly figured out why in a rudimentary way. And really, who cared as long as we survived. I would have guessed it was the bubbles. In the 1800s Louis Pasteur discovered that live yeast causes fermentation so he figured out how to effectively kill them off.  Finally, in the early 1990s a bacterial strain called “lactobacillus” was found in both fermented foods and in the human stomach naturally and independently. It was surmised that we needed these bacteria for efficient digestion and more. They were named collectively “probiotics” when they were added to one’s diet. 

A Little Science

The Oxford dictionary defines fermentation as, “The chemical breakdown of a substance by bacteria, yeast, or other microorganisms typically involving effervescence and the giving off of heat.” What in the world does that all mean to us, you may say? Well we use some of those critters to do our bidding. By adding them directly to our target and or by setting up a favorable condition for their success, they create and maintain an environment that kills or does not allow harmful bacteria to thrive. The trick with food is ensuring those favorable conditions. When we ferment food and beverages for our families we should feel the weight of our freshman biology professor saying,”Now, are the results of your experiment repeatable, and how are you so sure?”

Regarding fermented foods, there are a few things that can make you really sick, but there are only a couple that might, certainly can, kill you. Let’s deal with the most feared–botulism. The toxins of botulism are produced and thrive on low acid foods, like many vegetables, when they are moist and in a low oxygen environment. Wow, that sounds a lot like what we are creating. 

Fear not, for here is where we assume a little control and create the optimal environment for the good guys. In the lacto-fermentation process we use salt to encourage bacteria to make lactic acid which thereby inhibits the growth of the botulism toxin. The trick is to make it happen in good time. Acidity is measured on a PH scale with 1 being very acidic and 7 being neutral. Acidic foods that are considered safe to eat are 4.6 or lower. And what are the variables?; temperature, time and salinity. We have to balance these things to provide the optimal conditions for the good bacteria to work their magic and still taste good. Here is where culinary art and biological science combine. I occasionally use litmus paper to check the acidity of my pickles as they pickle and my vinegars as they convert from alcohol, not that I don’t have faith in the old tried and true recipes or trust a new one, but it is fascinating to watch and it lends a certain confidence in their safety. If you are just starting out, I highly recommend doing it a few times. When we get it right, the acid develops quickly enough to win the war but doesn’t become so strong that the product tastes awful.

To become successful — making your experiment repeatable, stick fairly close to tried and true recipes. Salt ratios are important. Too little salt and it might produce too weak a brine and too much salt and the fermentation may never start which won’t matter much because no one will eat it anyway, so too are temperatures. Natural yeast seems to be most efficient in the mid 70’s F (me too). Other  yeasts  have their optimal temperatures; time, well once the product makes it to the safe zone which we try to hit in a few days. Flavor and texture are often a function of time; sometimes longer is better and sometimes not. Those fermented spicy onions can be pretty strong after a few weeks at 75 degrees, but I did find some spicy carrots that were on the shelf at least six months and well, pretty sour, but not too bad at all on a sandwich. As you go along, you’ll know what I mean – don’t want to rob you of all the discoveries…

Kombucha

Sanitization

We can’t talk about food borne illness and contaminants without talking about means for preventing them. Even before the chemistry of creating a high acid , extreme alkaline, or high alcohol environment, we should consider the biology of cleanliness. When we ferment, we are asking specific microorganisms to perform specific duties. We need to get everything out of their way so they can do their job efficiently. Start by keeping everything clean. This includes your hands. Make sure you rinse everything off well. That antimicrobial detergent residue can wreak havoc with the taste of some things and hinders the growth of the good microbes as well as the bad.

Often people confuse sterilization with sanitation. Sterilization is the killing off of everything – not possible in the home kitchen. Sanitization on the other hand just kills off enough to let the good ones we introduce get the upper hand. Many fermentation projects only require cleanliness to be successful like pickles and sauerkraut. Others definitely need sanitation, like beer. I swear one too many bad bugs in the beer making process can make an entire five gallon batch smell (and probably taste) like old gym socks.

There are a number of sanitation methods: boiling, chlorine bleach solutions, oxygen bleach solutions, hydrogen peroxide, iodophor, and star san. I think iodophor and star san are the most economical because they are reasonably priced as they can be reused, they are fairly safe, they are effective and they don’t need rinsing. I’m sure there are others but I’ve used these and they all work fine.

If what you are doing requires sanitation, sanitize everything. I sanitize things that don’t even need it just because I might touch it then touch something that does, like the package of yeast before I open it and the scissors I cut it with. Hey, can’t hurt. I make up a batch and keep it in a one gallon repurposed wine jug and then put it into a bowl or a spray bottle for dipping or spraying then pour it all back when I’m done. If you are as frugal as I am, you’ll figure it out.

There you have it; a brief history and a little science, so please join me in another year of exploring and enjoying the wonders of fermentation; it’ll be good for you.

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Thomas Andersen Felton Fermenter
Thomas Andersen
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Tom Andersen is a writer, cook, martial arts instructor and lifelong Felton resident. He explores the world of fermented food and drinks in print and online. Tom lives in Felton with his family and many pets. He is currently working on a cookbook about fermentation.

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