Lactic Acid FermentationWhat is Fermentation?Fermentation is the anaerobic (without oxygen) breakdown of substances such as sugars and carbohydrates into other substances often acid or alcohol via microorganisms such as bacteria and yeast (1, 2). Microorganisms ferment to make energy, while acid, carbon dioxide, and ethanol (alcohol) are side products that we utilize (1). For food purposes, two different types of fermentation are most often used: ethanol and lactic acid fermentation (also known as lacto-fermentation). Yeast, specifically certain wine and beer strains or bread strains of Saccharomyces cerevisiae, which you can purchase, is generally used to make alcohol or bread, respectively (1). Carbon dioxide is released which is what causes bread to rise or it is off-gassed in the case of ethanol fermentation (1). In contrast, wild lactic acid bacteria, particularly certain strains of Lactobacillus, Leuconostoc, and Streptococcus, generally perform lacto-fermentation, although other bacteria may also play a role (1). Lacto-fermentation is used to make many common food products such as sauerkraut, kimchi, pickles, hot sauces, cheese, yogurt, and more (1, 2). A third type of fermentation sometimes performed at home uses acetic acid bacteria which are used to make vinegar and kombucha (2). Various fermented hot sauces and one of my favorite ways to use hot sauce, over eggs! Why Ferment?Fermentation is a form of food preservation. Before refrigeration, freezers, and safe canning equipment existed, fermentation was used to preserve the harvest and make food safer to store. Fermentation can also make food more nutritious and more digestible (2). Most cultures have food preservation techniques based on lacto-fermentation, ethanol fermentation, or both. I ferment not only to preserve the produce I grow but also because I like the taste. Fermented hot sauces and pickles taste different than a typical vinegar-based hot sauce or pickle. I am also prone to acid reflux and find that fermented foods are easier on my stomach than the typical vinegar-type pickle (although I love vinegar as well!). How to FermentFermentation is a very safe method of food preservation assuming you start with enough salt. A good rule of thumb is to use at a minimum 2% salt, although some vegetables require more. For example, cucumbers consist of a lot of water therefore, up to 5% salt is better to prevent mold formation. For a good chart on how much salt to use and more information on how to make up the salt solution, I like this website. Because fermentation is one of the safest ways to preserve food, I am often willing to follow random internet recipes for fermentation (unlike canning where I only follow safe, tested recipes) because generally if a fermentation goes bad, you know. Just double-check how much salt to add to that vegetable for any fermentation recipe. If your fermentation turns slimy or moldy (anything fuzzy), throw it out! What is commonly called Kahm yeast (a white coating on top of the ferment that is not fuzzy) is safe to eat but can give the food an off flavor. The key to successful fermentation is to keep everything below the brine and eliminate as much oxygen as possible at the top of the ferment. Anaerobic lactic acid bacteria grow without the presence of oxygen however mold contamination always occurs at the top of the ferment as it requires oxygen to grow. Once the fermentation gets started enough carbon dioxide is produced to push out excess oxygen and the risk of mold contamination is reduced. To keep oxygen from re-entering ferments I like wide-mouth mason jars (quart or half-gallon sizes are great), with glass weights to hold everything below the liquid brine and a lid to keep the air out. I often use the Easy Fermenter Lids or simple airlocks used for alcohol fermentation as they self-burp, so you do not need to keep opening the lids. If you use an actual lid you will need to release the gas produced often enough to keep the jar from exploding but you also run the risk of incorporating oxygen into the top of your ferment every time you crack the lid which can allow mold to grow. For larger ferments, you will likely want a fermentation crock. I like the water seal fermentation crocks with a lid in a moat at the top that holds water, forming an airlock. A small hole in the lid allows the gas to escape but the hole is covered by water to keep oxygen from entering the crock. A 3 gallon water sealed fermentation crock from Ohio Stoneware. The top moat is filled with water and the hole in the lid that allows gas to escape is visible in the second picture. Most fermentation crocks also come with stone weights to hold the vegetables below the brine. For a basic fermentation, you make up your salt solution (some things like sauerkraut are traditionally brined dry, meaning you add salt directly to the vegetables and the salt pulls liquid out) and pour it over your prepped vegetables. Make sure all the vegetables are covered, add your weight to keep the vegetables submerged, and attach the lid. Most ferments such as hot sauce go at least 30 days but commercially made Tabasco is generally aged 3 years, sauerkraut generally takes 6-8 weeks, and cucumbers are usually much shorter, 5-7 days although you can go longer if you want a sourer pickle. I tend to do shorter cucumber ferments to reduce the risk of mold formation and because I like crunchier pickles. In general, the longer the ferment the softer the vegetable will become. ResourcesFor sauerkraut and cucumber-fermented pickles, I follow Ball (one of the safe canning resources) recipes. Their online website only has a fermented tomato salsa recipe, but other fermentation recipes such as sauerkraut, pickles, hot sauces, and Worcestershire sauce are available in several of their books. See my Canning post for more information on the Ball books that are currently available. Pickles are more likely to mold in my experience, so I like the Ball recipe because it uses a little vinegar at the beginning of the ferment to help reduce the risk of contamination before the fermentation gets started. However, there isn’t enough vinegar added to inhibit fermentation. For fermentation resources other than Ball, I like the Insane in the Brine website, particularly for his hot sauce recipes. The author has also written a couple of books, which feature even more of his recipes than are available online. Other books I recommend include “The Noma Guide to Fermentation” by Rene Redzepi and David Zilber, “The Art of Fermentation” and “Wild Fermentation” by Sandor Ellix Katz, “Fermented Vegetables” and “Fiery Ferments” by Kirsten and Christopher Shockey, and “The Kimchi Cookbook” by Lauryn Chun. References
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As I mentioned in my previous post, garden huckleberries are a unique berry in the nightshade family. They are toxic when unripe, have little taste when ripe, but when fully ripe AND cooked, they are absolutely delicious and make a beautiful dark purple jam. After making a batch of garden huckleberry preserves, we still had quite a few berries left over in the freezer. Since my husband and I love fermentation we decided to experiment with a one-gallon test batch of garden huckleberry wine. We both have a Bachelor’s degree in biology and I also have a concentration in microbiology so we enjoy the science behind fermented foods and drinks, although neither one of us is an expert. Thus far we have made kombucha, sauerkraut, kimchi, wine and beer from kits, mead, and now garden huckleberry wine. We also currently have a maple wine (which smells absolutely delicious!) undergoing secondary fermentation and will hopefully be the subject of a future blog post. This summer we also would like to experiment with dandelion wine and a spruce-tip beer. We planted wine grapes on our property in the spring of 2017 which will hopefully produce their first grapes this summer (2019) on 3-year-old vines. These grapes, Marquette, are a red grape well suited to our climate (zone 4) however, they can be acidic as short/cool season grapes often have difficulty fully ripening. Therefore, blending is often used to reduce acidity and increase sugar content of these grapes if needed. However, as more growers are cultivating the Marquette variety, they are having success producing a very nice dry red wine or slightly sweet port that is not overly acidic. We are hoping in addition to making 100% Marquette wine we could also find some fruit or other grapes varieties to use for blending. Blackberries or raspberries are commonly used to make a delicious berry-Marquette port. When we realized we had extra garden huckleberries we thought it would be good to practice making wine from scratch rather than a kit and also possibly find a good fruit to blend with the Marquette grapes. In this post, I will assume that the reader already has some experience fermenting. If not, a good place to start is to buy a wine or beer kit, to first determine if you enjoy brewing. Once, you have tried a few kits, read a few books, looked at some websites, and/or listened to some podcasts, it is much easier to experiment with fermenting from scratch. To make our garden huckleberry wine we modified a recipe for blueberry wine (see our modified recipe below). As garden huckleberries must be cooked to bring out their flavor, I first cooked the berries with a little water and crushed them with a potato masher to release the juices. I cooked them for about 20 minutes added 1 tablespoon of lemon juice, cooked an additional 5 minutes, and then added the sugar to the berries and mixed until dissolved. Garden huckleberries are a very tough fruit with an almost leathery skin so in the future I may use an immersion blender to help pulverize the berries rather than just a potato masher. After the sugar was dissolved, we brought the water up to 1 gallon. At this point you can check the specific gravity to make sure the sugar content is correct, generally you want to start wines around 1.090 depending on what you would like your final alcohol concentration to be. When making a fruit wine you would generally add in one Campden tablet/gallon or potassium metabisulfite at the correct concentration to kill any wild yeast on the berries. Since we had just boiled our berries, I assumed most wild yeasts would be killed and skipped this step. We then added the tannin, acid blend, pectic enzyme, and yeast nutrient and mixed well. I am not sure if both the lemon juice and acid blend are necessary and may skip the lemon juice next time. The pectic enzyme will digest the pectin in the fruit which otherwise could make the must gelatinous; also excess pectin will also leave your wine hazy and keep it from clarifying properly. Yeast nutrient is used to help give the yeast a boost, yeast energizer can also be added or you can buy them already mixed together under specific brand names. If fermentation slows before completion you can spike in more nutrient and/or energizer to help push fermentation to completion. Some brewers also like to add in grape juice concentrate to their fruit wines, which increases sugar content so make sure to adjust final sugar levels to the correct specific gravity after mixing this in. This will also make your wine fruitier. As we wished to see what a pure garden huckleberry wine tasted like, we did not add any grape juice concentrate. The last step is to add the yeast. Since we had boiled the berries it was important to make sure the must was not too hot, you generally want it around room temperature. We used Lalvin K1-V1116 yeast which is supposed to be good for fruit wines and also has a high alcohol tolerance (18%). This was also important since we wanted to make sure it would ferment to dryness. We dry pitched the yeast and stirred it in, however, most yeast packets will recommend activating the yeast prior to pitching. If you activate first, make sure you follow the instructions exactly as written, otherwise you may shock the yeast too much which will prevent fermentation from starting. We fermented in a 2-gallon bucket fermenter that we had cleaned with one-step cleanser and sterilized with potassium metabisulfite. Make sure everything that comes in contact with your must is as sterile as possible. After everything was mixed well, we covered the fermenter with a lid containing an airlock to let out the CO2 gas released during fermentation. Generally, you should see bubbling in the airlock within 24-48 hours. With most fruit wines you want to stir the must 1-2 times per day, otherwise the fruit cap will stay on the top and you will have less flavor and color released into the liquid. The more the cap comes in contact with the liquid. the more color, flavor, etc. will be released into the wine. The wine will likely ferment for approximately 2 weeks or even longer depending on the type of yeast used. When bubbling starts to slow you can start testing the specific gravity with your hydrometer and when it reaches 1.010-1.020 you can rack it to a secondary fermenter (a 1 gallon glass carboy/jug) or you can leave it in the primary until it completes fermentation (specific gravity less than 1). Before racking you must strain out the berries and debris and move the wine to a cooler place if possible, to clear. Every week or two, as more debris settles you can rack to a new 1-gallon jug. At this point if fermentation is complete you can cap the jug or use a bung and not worry about the airlock. Make sure fermentation is 100% complete as we have had a batch of mead blow the bung out of the jug when we removed the airlock too soon. You can also add a Campden tablet after each racking or just wait before bottling if you do not like to have too high of sulfite levels in your wine. I do not like to use more than 2 tablets/gallon of wine total. Those who are sensitive to sulfites may wish to try even less or skip it altogether although this does increase the risk of contamination. Once the wine has clarified to your liking you can bottle the wine and age it, generally 3-6 months minimum. If you prefer a sweeter wine you can back sweeten before bottling but you must add in potassium sorbate to prevent fermentation in the bottle. You can also add in potassium sorbate if you wish to age your wine longer and prevent spoilage. We tasted a glass of our wine before bottling and were very impressed by its taste. It was slightly sour (maybe skipping the lemon juice next time would be better), slightly bitter and tannic, with definite flavors of garden huckleberries. Although it started out as a very dark purple color it mellowed to a more red-purple color. If you prefer your wines with more intense flavors you can add more than 3 lbs of fruit and if you prefer them lighter, you can add less. Overall, we liked the initial flavor of the wine well enough that I started dozens of garden huckleberry plants this spring (as opposed to the 6 plants we had last year) so we can hopefully make a larger 3-5 gallon batch next year. Garden Huckleberry Wine Recipe (1 Gallon)3 lbs berries (garden huckleberries, blueberries, or other berries) 1 T lemon juice ~1.8 lbs sugar 0.5 tsp acid blend 0.5 tsp pectic enzyme 0.6 tsp yeast nutrient 0.2 tsp tannin Campden tablets (1 tablet per gallon) 1 package yeast (Lalvin EC-1118, Lalvin 71B-1122, Lalvin K1-V1116, or others) |
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AuthorIn 2016, my family and I moved from the New York City area to small town Wisconsin. Our move, this website and blog (and our previous Etsy store) is the result of our desire over the past several years to simplify our lives, increase our quality of life, reconnect with nature, and enjoy a more self-sufficient life. I grew up as a country kid in central Pennsylvania working on my grandfather's fruit farm and as a corn "de-tassler" at a local seed farm. My background is in biology where my love of nature originated. I am a former research scientist and professor and have now transitioned to a part-time stay-at-home mom, self-employed tutor, and small business owner. Thank you for taking the time to check out my site. Archives
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