As a lover of all things spicy, I set out to find out how to do it but I was disappointed in the lack of good step-by-step instructions. Once I pieced it all together and made my first successful batch, I naturally decided to write an instructable on it and share the acquired knowledge.
Step 1: Ingredients
• Filtered Water
• Greek Yogurt with Active Cultures
• Cutting Board
• Metal or Glass Bowl
• Small Sauce Pot
• 2 Glass Bottles or Mason Jars
• Immersion Blender
• Air Lock
• Fine Mesh Sieve or Cheesecloth
• Small Bowl
Step 2: Warnings & General Information
I'm sure I don't have to remind everyone that knives are sharp and boiling water is hot, what I may have to warn about is the peppers. Capsaicin, the molecule that gives peppers their "heat", is extremely irritating to the mucous membranes of the eyes, nose, throat, mouth, lung, and (not to be crude, but this is important) the genitals. I say this because capsaicin-containing oil from peppers can stay on the skin for days and can be transferred to anything (and anywhere) your fingers touch. In extreme cases it can result in hospitalization.
While all this is probably obvious to those of use who have handled hot peppers before, what may be less obvious is the air above hot peppers is equally noxious when breathed in. This can happen even when the peppers aren't being cooked. What happens is, when the protective cuticle of the pepper skin is cut (or in our case pureed) aromatics and volatile compounds become airborne. Since capsaicin is both volatile and aromatic, it is easily dispersed into the air. The rate at which this happens is compounded with increased surface area, heating and fermentation (where it "hitches a ride" with off-gassing CO2), all of which we are doing in this instructable.
So remember to wear gloves and work with ample ventilation. If your air passages begin to burn, remove yourself from the area immediately. If you get pepper juice onto your skin, wash with ample soap and water. If you get pepper juice in your eye, rinse immediately with milk (any non-skim milk will do, the more fat content the better) then flush with water. Capsaicin is not water soluble, so it needs something in which it's long chain fatty acid side chain can dissolve (oil, milk, soapy water, alcohol) and/or a detergent that will remove it from the associated pain receptor (soap or casein in milk).
About a year or two ago I came across an incredible article on the fermentation of foods and beverages that summed everything from history to health up nicely. Unfortunately, my brain is like a sieve and I cannot remember which magazine or journal it was in or if I saved it in the stacks of Nature, Scientific American and Popular Science I have in my basement. That notwithstanding, there's still plenty of articles abound about fermentation and how it works, the history of it and the benefits. Be judicious in your research, while there is scientific backing and/or strong theory behind a lot of the health claims being touted, be wary of anyone claiming fermentation (vis-à-vis probiotics) is a panacea for all things that ail us. The microbiota of our gut is a strange, complicated and ever-changing world that we are just beginning to understand. That said, there is a growing body of research showing the clear and many benefits of probiotics.
About Hot Sauce (and Spicy Food in General)
Hot sauce does more than just jazz up bland food. It is reported that it aids in weight loss, fights cancer, lowers blood pressure, reduces inflammation, and improves mood. That last benefit is due to the release of endorphins, the happy chemical in your brain. It's this reason that has been attributed to more adventurous people liking spicy foods! All those benefits are just from the capsaicin in peppers, that doesn't even touch the health benefits of Vitamin C and flavonoids commonly found in hot sauce!
All the science and gobbledygook aside, fermentation makes some darn good food and drink. Without it we wouldn't have wine, chocolate, sauerkraut, pickles, soy sauce, beer, and of course hot sauce. Our main goal is to make something tasty, any health benefits we get from it are an added plus!
Heck, even the USDA (U.S. Department of Agriculture) has a section on fermentation in their surprisingly comprehensive Complete Guide to Home Canning, which I recommend everyone who is interested to read and reference.
Step 3: Prepare the Ingredients
Once the water is boiling, add ½ to 1 tablespoon of salt for every cup of water. You can play with the amounts of salt, but it is important that you use it since it creates an environment that favors lactobacillus fermentation. Stir until the salt is dissolved.
Step 4: Combine and Puree
Take your immersion blender (a.k.a. magic wand of the kitchen) and puree the peppers and brine as much as you can. Immersion blenders make quick work of this process, though you can also use a blender or food processor. You will want to do this with ample ventilation because you'll be breaking open the peppers' cells and the steam from the water will help carry that capsaicin right up to your nostrils.
The resulting puree should be of the consistency of a thick soup, not a stew. If needed, mix in some more brine. Remember it's always easier to add more brine than remove it.
Step 5: Whey Cool
The best way to harvest your whey is to take a small clean (preferably sanitized) bowl and suspend cheese cloth or a fine mesh sieve above it. Then spoon your yogurt into the cheese cloth or sieve, cover tightly with plastic wrap and put it into the refrigerator overnight.
The cloudy liquid that collects in the bowl is whey and in it is the lactobacilli (and other organisms) that will be doing our lactic acid fermentation. If your yogurt isn't fresh or if you're making a lot of sauce, consider making a starter in a clean bottle or mason jar with a 2:1 solution of water:sugar.
Step 6: Combine Ingredients
I recommend using a sanitized 12 oz. or 22 oz. bottle with a No. 2 drilled bung (stopper) and an air lock. This allows for gas to escape while fermentation occurs while also preventing anything from getting in. Do not reuse this bung and airlock in anything but lactic acid fermentation. You can use a mason jar, but you will have to regularly open the top to allow gas to escape.
Step 7: Fermentation
The two requisite cultures found in yogurt are Lactobacillus bulgaricus and Streptococcus thermophilus (U.S., I'm not sure of other countries). Both of these are homofermentive cultures, meaning they make only lactic acid while fermenting. Cultures that are predominantly or exclusively made up of these two species of bacterium may not form any bubbles at all while fermenting. However many yogurts also contain Lactobacillus casei, a heterofermentive species that will also produce CO2 when fermenting, which which along with other heterofermentive strains may cause bubble formation.
Stir your fermenting hot sauce regularly by quickly moving the bottle in a circular motion on the counter. During the early stages of fermentation, aim for stirring 3-5 times daily tapering off to once a day towards the end of fermentation (approximately 2 weeks). You can be somewhat lax in how often you do this, it won't affect fermentation too much but it will ensure a more complete and expedient process.
You can still get fermentation without using whey at all, though if you go this route make sure the brine is at room temperature before adding it to the peppers. This is historically how fermented foods were made, utilizing a brine solution and the endogenous microorganisms on the surface of the fruit/vegetable.
Step 8: Filter, Rinse, Repeat
Once fermentation has ended, in about 2 weeks, you can pour your fermented pepper puree through a sieve or cheesecloth into another clean bottle. You can either stop here or extract more from your fermeneted puree by mixing it with vinegar overnight (rinsing) or by starting the process over again by adding new/fresh pureed peppers and brine.
During pepper harvesting I kept the process going by continuously adding new puree to the bottle. Fermented peppers are pretty shelf-stable so even after fermentation was over I would just leave it on the counter. In fact, we moved some of our pepper plants inside and continued to harvest into late fall/winter using the same puree we started with in the summer.
Step 9: Enjoy
All that's left to do now is enjoy your hot sauce and take pride in the pain, I mean pleasure, it brings!
I keep my finished hot sauce in the fridge, though that's probably unnecessary.