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There are many recipes which claim to be Apple Cider Vinegar on the internet, but unfortunately too many of them are not the real deal. They are diluted versions of Apple cider vinegar, and we need to understand what the difference is and how best to use them. Below is an excerpt from our book ‘Life on Fodder Farm – A Journey to self-sufficiency’.
With many uses in the home and garden and a way to preserve the harvest itself, vinegar making is an important aspect of living with the land. The process is relatively simple but can have varying results depending on what method is used. Because it utilises yeast as the initial fermentation you can use the naturally occurring wild yeasts which will be present on homegrown fruits and veges. The issue with this is it can be unpredictable in its end result and tastes. By using a wine yeast in the initial fermentation, especially for fermenting fruit juices, you are more likely to end up with a pleasant tasting end result. We find using a fruit juice and doing a closed ferment into alcohol prior to doing the open ferment into vinegar gives the best results. This method creates a fuller bodied, stronger and better flavoured vinegar than the popular fruit scrap method, which uses fruit scraps, water and sugar.
From left to right. Apple cider vinegar, vinegar mothers and scrap apple vinegar.
If you are aiming to create a vinegar for adding to your preserves, it is recommended that it is at least 5% acidity to keep bacteria at bay. This is easy to measure if you are making the vinegar from fruit juice using a hydrometer or brix refractometer, as the sugar content sets the alcohol percentage which roughly translates to end acidity percentage. 1° Brix is about 0.5% alcohol which equals about 0.5% acidity in vinegar, so your initial brew would need a brix of 10 to create a 5% acid vinegar. To work out the calculation accurately the conversion is usually more like 0.8% acidity to 1% alcohol, so if you divide the alcohol percentage by 1.25 this will give you a more accurate measurement of end acid percentage. It is more reliable than using the pH testing as, depending on what the vinegar is made from, the pH can vary in its acidity percentage. When making fruit scrap vinegar this is harder to measure and unless you add the right amount of sugar to bring up the brix levels, its final acidity is unlikely to be strong enough for preserves. Be aware though that adding to much sugar can also affect the vinegar development as acetic acid bacteria is not usually active at alcohol percentages above 10, this is important if turning wine into vinegar as dilution will be needed. If you need to increase the brix of the juice, 15 grams of sugar per litre will raise the brix by one degree. So for a juice with a brix of 10° you would need to add about 45 grams of sugar per litre to get a brix of 13°, which would give you and end acidity of about 5.2%. The alcohol percentage can also be calculated by taking a specific gravity reading before and after the alcohol fermentation.
Ph testing is useful in determining how well your vinegar will store as bacteria and mold can develop in anything over 4 pH. When developing vinegar, you are aiming to be lower than this. Interestingly the pH scale is similar to the Richter scale in that each level’s pH is 10 times as acidic as one above.
Because the vinegar is acidic it can corrode some containers, so it is important to use suitable brewing and storage vessels. For the initial brewing, which can often be large amounts of liquid, food grade plastic buckets or brewing barrels are useful as they are easy to attach an airlock to if needed. Stainless steel, glass or the traditional wooden barrel can also be used, but for the open-air stage of the process you will need it to be a wide mouthed vessel to allow for better air exposure. If making smaller amounts large glass jars are the best option. To store the vinegar long term use glass bottles or jars and a tight-fitting lid as continued air exposure will eventually reduce the quality and acidity of the vinegar. Make sure any non-acid resistant lids are not touching the vinegar. Before starting the process, your brewing vessel should be clean and if possible sanitised to reduce any contaminates which can affect the end result.
Lemon peel and vinegar cleaner.
Besides preserving and pickles, vinegars can used be in the kitchen for salad dressings, as a rising additive in baking, marinades for meat and vegetables, as a health tonic and in herbal preparations. But it also makes a great household cleaner especially when combined with citrus as in the cleaners in chapter one. We use it outside too, as an extractant for making eggshell (calcium) and burnt bone (phosphorus) fertilisers for the garden. Apple cider vinegar is popular as an anti-fungal spray for fruit trees at the rate of 1 Tablespoon of vinegar per litre of water and sprayed in the evening, after rain or early morning. It can also be used as a weed killer at a lower dilution rate. Add about two cups of apple cider vinegar, half a cup of Epsom salt in 4 litres of water. Mix, pour into a spray bottle and spray directly over the weeds. Natural weed killers like this are best used on a hot sunny day. Vinegar will also remove rust, so great for cleaning your tools or those old bolts on upcycled projects.
Apple Cider Vinegar
True apple cider vinegar is apple juice, which is first fermented to an alcoholic hard cider, then exposed to air, and the naturally occurring acetic acid bacteria, to convert to vinegar. The apples are juiced, or the traditional method of crushing and pressing are used to release the juice, which is then placed in a wide mouthed fermenting vessel. If wild yeasts are to be utilised the vessel is covered with a loose lid or finely woven cloth to prevent contamination from fruit flies or other debris. The skins of homegrown fruits should contain all the wild yeast you need to get fermentation started. The juice will bubble and may foam up as it ferments the sugars, this should take a few days if in a warm environment.
For a more controlled ferment the juice has a wine or champagne yeast added to it. You may wish to kill any wild yeasts first by adding Campden tablets to the juice. Wait another 24 hours before adding the wine yeast otherwise it will kill that too. During this time leave the juice covered only with a cloth to allow the sulfur to dissipate as a gas. Once the wine yeast has been added put a tight-fitting lid on the fermenting vessel, with an air lock to release the fermentation gases. Once bubbling stops remove the airlock and lid and cover with a finely woven cloth to allow the air to access the brew. The acetic acid will start to convert the alcohol to acid. This can take a few days to months, to speed it up you can stir the brew to aerate it, add some raw apple cider vinegar or a live vinegar mother. A mother is a biofilm composed of a form of cellulose, yeast and bacteria which forms on the top of live vinegars. It is also called a Scoby, which is an acronym for “Symbiotic Culture of Bacteria and Yeast”. Anyone who makes kombucha will be familiar with Scoby’s.
Moving the mother to another brew transfers all the bacteria you need to start acidification of that brew. Regular tasting, smelling and testing of the pH should tell you when it is done. Shop bought white vinegar usually has a pH of about 2 to 2.5, but anything under 4 pH will not grow mold or bacteria. So, once it tastes and smell right to you and the pH is 4 or lower it is ready to be bottled. If left too long, it will continue to ferment and can actually lose flavour. Generally, fermentation will take a few weeks to a few months, over this time a mother should form over the vinegar.
Having spoken with several ex-commercial brewers recently several of them have said they will leave it for a year or two (in a home situation) to fully develop the acetic acid before bottling. In a commercial operation, tests would be done to measure the acetic acid. It is at this stage that water may be added if the acetic acid is too high. Most vinegars sold in New Zealand are 4% acetic acid, USA guidelines recommend all vinegars for preserving are 5%. Vinegars with a higher acetic acid percentage (such as 9% cleaning vinegar) are not suitable for consumption.
If you are interested in testing your vinegar, here is a video explaining the process
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- Crushing/mincing the apples.
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- Pressing the apple pulp.
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- The initial alcohol ferment.
Fruit Scrap Vinegars
This method develops a less flavourful and beneficial vinegar than the true Apple cider vinegar, but it is still a useful product. It is also a handy way to use up peels and scraps from preserving fruit. Pack the fruit scraps into a large jar to about ¾ full, because there is limited juice the scraps will need to be covered in water. To increase the strength of the vinegar sugar will need to be added to feed the fermentation. This is where a bit of experimentation can take place, the amount of sugar really depends on the sweetness of the apples and that is hard to measure when adding water to them. The water will dilute the natural sugars in the fruit scraps so adding one to two tablespoon per cup of water should bring this up to the needed brix. Full the jar with the sugar water to about 5 cm below the rim.
The scraps need to stay submerged in the water or mold can develop which will ruin the taste of the vinegar. You can either place a fermentation weight on the scraps or stir at least once daily to ensure the scraps do not just sit on top of the liquid. Cover the jar with a fine woven cloth or a fermentation lid and let it ferment for about two weeks in a warm spot but not in direct sunlight. Once the bubbling stops strain the scraps from the liquid and pour the liquid back into the jar. Cover the jar with a cloth to allow the naturally occurring acetic acid bacteria to access the brew. To speed up the process you can add a tbsp of raw vinegar to the brew.
Allow the brew to ferment for another four weeks or so, then taste it to see if it has reached a vinegar level you like. Bottle the vinegar when it is to your taste.
In some brews a thin white layer will form on the surface, this is kahm yeast and is harmless, it occurs when the sugar has been fermented and if the pH is low. It is the blue and green mold which taints the taste, but it can still be used for cleaning, however brews with black mold should be discarded.
Apple Wine Vinegar
This method is commonly touted as real apple cider vinegar but made in much the same way as the scrap vinegar. Whole apples are cut up instead of using just the scraps though. We have named it apple WINE vinegar as this is the process we would use if making a fruit wine from plums, feijoas, or other fruits. The fact is you are still diluting the apples with water and adding sugar. This immediately makes it not apple CIDER vinegar.
The process also means you cannot accurately measure the possible alcohol content unless you do an initial must ferment (as in wine making, usually about three days) then strain off the solids and take a specific gravity reading. You can then adjust the sugar content to achieve the desired end percentage and do a closed ferment. Once the ferment has finished the brew is exposed to air as above.
This process, while giving you a much better-quality vinegar than the scrap vinegar, is still a diluted apple vinegar based on sugar and water. This means the malic acid content will be lower than real apple cider vinegar, and this acid is the one that has the health benefits.
Wine and Kombucha Vinegar
Any homemade wine can be turned into vinegar, but as wine usually has an alcohol content higher than 10% it will need to be diluted down to below this percentage for the acetic acid bacteria to convert it to vinegar. For a 13% wine you would need to add about a third of its volume in water to lower the percentage to under 10%. Adding raw vinegar will speed up the process. Leave, covered with a cloth, to ferment until the desired pH or taste is reached.
Kombucha is even simpler as you can just leave the kombucha to continue brewing with its Scoby until it has reached the desired pH or taste. This vinegar will not be suitable for preserving.
There are other vinegars that can be made at home, but the methods above use readily available foods and are simple to make.
For more information, ideas and inspiration on living a more self-sufficient, self-reliant and natural life our book ‘Life on Fodder Farm – A Journey to Self-Sufficiency’ is available in all good bookstores or from our website.
