Lactic Acid Bacterial Serum

Posted by on July 13, 2015

Lactic Acid Bacteria (LAB) are everywhere. Lactic acid is found in milk. LAB consume the milk sugars (lactose) and utilize enzymes (lactase) to produce a waste product that is lactic acid.

I am a huge advocate of raw milk, which has not been pasteurized nor homogenized. The milk exits the cow without any microbial life in it (unless it is a sick cow or it has mastitis… A boob infection). LAB in the air and on surfaces will easily colonize the milk.

Fresh raw milk is sweet and after a week, it begins transforming into clabbered milk, yogurt, cheese, and other sour variations of milk as the sugars are converted into lactic acid. It is absolutely safe to drink after a week, but the flavor becomes something I do not care for in my milk. It is great for naturally cultured butter, but I digress.

Here is the quick version of my method that has done so much in the past 3 years since I learned this method….

Shake some rice (any rice… The more natural, the better) in some water. Strain the perfectly good rice for your dinner and save the cloudy water. Keep it covered with cheesecloth and out of direct UV (sun) light for about a week… Longer in the winter, less in the summer.

The starchy water will develop a skin on top, sediment on bottom, and a fat midsection of semi clear liquid. Use a turkey baster, oral syringe, etc to draw out the middle liquid and place it into a jar of milk (any milk… Raw is best, UHT is worst). Let the milk sit warm and without UV light for about a week depending on temps.

This last stage should happen anaerobically (without oxygen). Be careful of building gasses during the last stage… Use a ball jar without tightening the lid or use an airlock from brewing gear.

On to the details:

Your choice of water will likely have the biggest effect on the final product. You do not want chlorinated water since chlorine kills bacteria indiscriminately. Distilled water is too sterile and lacks micronutrients, but that will only slow progress.

Instead of rice, you can use other starchy materials… Potatoes, barley, wheat. You want to avoid simple sugars, honey, syrup… The starches provide a food base for bacteria in the air to colonize your water. It will attract a broad spectrum of bacteria and allow them to grow in number. It is how you collect the seeds of your LAB serum. You should see the layers form within a week or so.

You want the starch water to breathe. A thin layer of cheesecloth covering the jar will prevent flies and mosquitoes (and whatever else) from depositing eggs, but will allow bacteria to colonize the starch water.

UV light will kill most bacteria within minutes. Protect your jar from seeing direct sunlight at all costs.

Your collection phase with the starch water will collect the specific strains of bacteria present in the collection site. Place it in your house, near the garden, in the woods, near compost.

The top layer of the undisturbed starch water is mold and Bacterial byproducts. The gritty bottom is carbohydrate and sediment. The liquid in the middle region is known as rennet and is very high in lactic acid bacteria and other bacteria as well. Rennet is used in cheese making, so you will smell sour cheese in a healthy finished product. Expect a mild odor… Nothing too offensive.

Mix 1 part of this rennet/starch water with 10 parts milk. The milk acts like a lens does for light. It focuses the broad spectrum of bacteria from the starch water and provides a specific environment where LAB thrive and out compete other bacteria.

The fermentation that occurs gives off gasses. By the time it is ready to use, it will explode a glass jar. Be sure to set the lid loosely or use an airlock device that allows gasses out, but no outside air to get in.

The time spent in the milk will focus the range of bacteria present. It is highly friendly to the bugs we want and inhospitable to other kinds of bad bugs.

After a week (depending on temp), you will see curds forming on the top. Feed these to your chickens,pigs,dog,cat…. It should have a sour cheese like smell to it. It isn’t real pretty, but it should not be too offensive. A strong rotten smell may be a sign that something did not work out with the batch and you should consider flushing it or possibly adding it to your soil.

The liquid portion of your finished LAB serum is highly concentrated lactic acid bacteria containing specific species and strains of the bugs that make your location ‘work’ and function as an ecosystem. It will generally be diluted in a 20 parts water to 1 part LAB serum. This is a fat 3 tbsp (a light 1/4 cup) per quart of water.

This will store for 3 months if refrigerated.

You can make it shelf stable (no refrigeration needed) for a year by adding an equal amount of blackstrap molasses as food for the bacteria. 1/2 serum, 1/2 molasses.


Pour a 1/4 cup of straight serum down a drain or through your toilet once a month to keep your septic system clean and free of buildup.

Pour 2 tbsp into a clogged drain. Use 1 tbsp in a 12 oz bottle and pour into a slow drain overnight… The bugs will eat your clog if you do not flush them through by using your sink for a few hours.

Spray the 20:1 mix on leaves to improve plant growth. Drench soil near the roots of crops to break down organic matter into plant food and to combat bad bugs near your roots. Use it to combat powdery mildew on squash and other plants.

Spray 20:1 on critter areas to reduce smell and to speed up decomposition of their waste. This works on all kinds of critter poop and organic stink.

Use it to ignite compost, or to rebalance an imbalanced (stinky) compost pile. To ignite a pile, use a cup full strength then turn your pile/bin to spread out the LAB serum. This will help to out compete pathogenic or stink causing bacteria. It will add millions of bacteria to kick off the process of turning organic waste into perfect compost.

Add a few drops to a gallon of water and feed it to your critters… Or drink it yourself! It helps to extract more nutrients from the same amount of food, higher energy levels, and a stronger immune system (anecdotally). I can attest to my chickens and rabbits consuming less food and creating smaller and fewer poops when this is added to their diet.

Spray 20:1 in your garbage cans to freshen them up. Use 1/4 cup of serum in your washing machine and leave the water sit for a while to freshen a stinky washer.

Basically, it reduces organic stink, improves digestive function, and combats bad bacteria.

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