Perhaps for thousands of years humans have been purposely, and sometimes accidentally, fermented sugars and starches into vinegar. Vinegar, used in food and herbal preservation and given its accompanying health benefits, is an important part of the home herbalists tool box. Vinegar is excellent for preserving nutritive herbs as it extracts minerals such as calcium. It also is used in herbal medicine in combination with alcohol to capture alkaloids from certain plants. Likely vinegar was historically replaced by synthetically made acetic acid for stabilizing toxic botanical alkaloids in pharmacy medicine. Herbs with pungent and aromatic qualities work well extracted in vinegar.
Apple cider vinegar is most commonly used but vinegar can be made from most fermentable carbohydrate rich sources such as wine, grain, potato, beet, sorghum, honey, berries and fruit. As the sugars in these foods are fermented by yeasts and other helpful microorganisms it turns into alcohol. Vinegar is essentially this alcohol cultured by Acetobacter bacteria (acetic acid) when exposed to oxygen. This bacteria is what makes vinegar sour. Since vinegar is made from plants the acetic acid levels are variable. Store bought vinegar is diluted with water and brought to a consistent five-eight percent acidity. Amounts over ten percent are considered an irritant. Unpasteurized vinegar contains a mother culture of cellulose and bacteria, called Mycoderma aceti, as well as mineral salts, vitamins, amino acids and polyphenols.
Medicinal Uses: Often in herbal books it mentions that vinegar tinctures are not as strong as those made with alcohol. It’s true that vinegar is a different solvent than alcohol as far as what it might extract. However I am hopeful vinegar, as an easy to make home remedy, can be revived as a more than just a weaker substitute for alcohol. Vinegar has a long history of use and likely has more to offer than expected.
Vinegar is considered cooling in nature, a respiratory expectorant and a topical antiseptic for skin and internally to mucous membranes. It is a good solvent, in varying degrees, for extracting from herbs rich in the following: minerals (salty), alkaloids (acrid or bitter), volatile oils (aromatic), and alkaminides (pungent). Given this we can play around with what situations or kinds of herbal preparations make sense.
Vinegar makes a good vehicle for preserving mineral rich spring greens like nettle, chickweed and dandelion greens. From there this mineralized vinegar is a starting point for salad dressings for vegetables or added to bone broths.
Method
There are several ways to make herbal vinegars. Always start with a clean and dry jar. For culinary use chop a single fresh herb, for instance rosemary, place in a loose pack in a jar and cover with vinegar. Taste it as it steeps straining when you like it. If minerals or volatile oils are the medicinal target use a weigh and measure preparation. Use freshly dried or high quality dried herbs in roughly a one:four ratio, more or less depending on whether it is a leafy plant or a root or how ‘fluffy’ the plant material. The one is the weight of the plant in ounces (or grams). The four is the volume of liquid in ounces (or mL) in relation to the weight. For example to a harvest of four ounces by weight of freshly dried nettle leaves add sixteen ounces of vinegar by volume to cover. To finish both methods, cover with a plastic top or a metal top with parchment paper between the vinegar and the lid. Shake daily and let sit for about four weeks in a cool dark place. Strain herb, compost and bottle infused vinegar. Label with date, kind of vinegar and herb used. Renew every year.
Resources
https://www.urbanmoonshine.com/blogs/blog/diy-herbal-vinegars
The Modern Herbal Dispensatory
Herbal Education 