How is vinegar made, and how does it improve preserves?
This time we looked at old and modern ways to preserve the flavour and aroma of the season using vinegar, alcohol and a clean jar, but also freezing, oil or salt. Will you try raspberry vinegar, preserved currants, or blackberry chutney?
1. Playing with vinegar
A common preservative, vinegar creates a highly acidic environment, killing microbes and changing the taste and texture of food. Almost all fruits and vegetables, flowers, shoots and other fruits, even unripe ones such as green tomatoes, strawberries or almonds, are pickled in a minimum 5% solution. Cooks alternate between sour and sweet and also different types of vinegar, from white wine vinegar to cider vinegar and various flavoured, fruity and herbal vinegars.
Just infusing vinegars (and oils, too!) offers another option to preserve the aroma of the ingredients and lend fresh summer notes to salads, marinades, roast meats or even drinks. Jars filled with elderflowers, lavender or roses, but also sprigs of rosemary, watercress, parsley or violets, are covered with warm (not hot!) vinegar. They are then left on the windowsill for about two weeks, after which they are drained and refrigerated.
Tip: Popular are so-called "shrubs", syrups made from fruit and vinegar. They are made by macerating ripe fruit in equal amounts of sugar and vinegar and encourage bartenders, baristas and chefs to experiment. The mashed, chopped or grated fruit mixed with sugar is turned into a syrup after one or even several days in the fridge, which is strained, combined with juice squeezed from the remaining pulp and topped up with vinegar, usually apple cider vinegar. Recipes also offer champagne vinegar, which goes well with peaches and apricots, or balsamic vinegar, which goes well with strawberries and black pepper. The leftover fruit can be used for ice cream or baked desserts, but it can also be preserved in brine for a nice tang.
2. Alcohol
There is also a long tradition in Europe of using fruit in alcohol, which, like salt and sugar, removes moisture from food and stops micro-organisms from becoming active. Since about the 18th century, short-season fruits have been preserved in brandy, rum or gin and various spirits. Spicy peaches, apricots or plums are added to roast meat, but also heated and softened with butter, cinnamon, whipped cream or ice cream.
Rule: The optimal result is achieved in a brine with 14-20% alcohol. In a weaker solution, the fruit or vegetable will begin to ferment, while a higher concentration can cause the raw material to harden as the alcohol draws too much water out of it.
The German Rumtopf method: Mix the halves, slices or larger cubes of 6 ripe peaches in a bowl with 2 to 4 cups of granulated sugar, put them in a jar and pour in two cups of brandy so that the fruit is completely submerged. Whole cinnamon, cloves, star anise or vanilla bean may also be added. The fruit is refrigerated for about four weeks and finally moved to the fridge, where it will keep for up to six months. The remaining juice can be used in a sauce - it is simmered gently with the meat stock and after 10 minutes softened with butter and seasoned with a sprig of thyme, salt and pepper.
3. Dry preserving
A common thing for our ancestors, but more of an experiment for cooks, suitable for preserving small berries such as currants, gooseberries or perhaps pine nuts. As the name suggests, the technique involves sealing the intact (!) berries (ideally with the stem) in clean jars. It is best to pick the fruit directly into sterilised containers or to close them within 15 minutes of picking, so that a protective atmosphere forms around them and they do not spoil.
Tip: You can try using wild mulberry, toadflax or barberry.
Without access to air, light and heat, the fruit ferments and fades slightly over time, yet retains its flavour, aroma and usually its texture. The uses of the fruit are virtually the same as for fresh fruit - they are used to garnish yoghurt, ice cream, desserts and salads, bake cakes or mix pesto and various marinades or salsas.
Extra tips:
Other preserving techniques include oil pickling, which prevents air from entering, protects food (vegetables, mushrooms and herbs) from bacteria and mould and slows down oxidation. Thanks to the oil 'film', the fresh colour of the ingredients, especially herbs, is thus preserved along with the flavour.
The classic method is freezing. However, it has a few rules. Ripe fruit or vegetables should first be cut into small pieces - the more slowly the raw material freezes, the more ice crystals form, which can damage it. Freezing will be speeded up not only by the smaller size of the fruit, but also by having enough space between them. Cooks will use a freezer freezer, a professional freezer or liquid nitrogen to ensure the result.
Enzymes in vegetables and fruit can cause colour fading after freezing, so it is recommended to blanch vegetables in boiling water before freezing to deactivate the enzymes. Similarly, it is worth spreading the fruit on baking paper, allowing it to dry, pre-freezing it before putting it in bags without excess air and returning it to the freezer. Fruits and vegetables freeze faster, but they also don't stick together and separate better when removed from the freezer.
Some watery and delicate vegetables, such as tomatoes or aubergines, don't freeze as well and change colour and texture, so it's better to make a sauce or puree them with a little oil and herbs. They can keep in the freezer for up to 18 months.
Marie B. Svobodová gives a simple recipe for raspberry vinegar: Pile half a litre of red raspberries into a bottle, top with a litre of vinegar and leave the whole thing to sit for six days. The opening of the bottle is just covered to prevent insects from getting in. It is then poured off through a cloth into another container, and when the vinegar has settled in about two days, it is strained into smaller bottles, sealed and stored. To make lemonade, the vinegar is boiled with sugar in a 1:2 ratio, while without sugar it is served with fish, especially trout, but also in sauces and salads. For a more intense result, a kilo and a half of raspberries are processed per litre of vinegar.
In the cookbook you will find gutter compote, which is poured over a pint of plum brandy boiled with 130 g of sugar, or a mixture of seasonal fruits with rum. The fruit is picked into a glass, sprinkled with the same amount of sugar and poured over a little rum for flavour. Add the zest of half a lemon and half a vanilla pod. The compote is delicious with a roast or as a dessert garnish.
The summer aroma releases into the food and different flavoured salt such as herb or currant salt. Store it in the freezer with minimal air access.
The jam shelf will be enlivened by fruit mustard, or mostarda. It comes from Italian cuisine and goes well not only with cheese and cured, smoked or roasted meats, but also with carpaccio or in sandwiches. There are plenty of recipes - the basis is juicy fruit, mustard seeds or mustard powder, sugar or honey and salt, or good quality (apple or white wine) vinegar or wine and orange or lemon juice.
An interesting variation on marmalades is also chutney, For example, from blackberries: put 500 g blackberries, 140 g (icing) sugar, 140 g sliced red onion, 3 teaspoons chopped ginger and 2 teaspoons Dijon mustard in a large saucepan and cook over a low heat, stirring constantly, until the blackberries burst. Then add salt and pepper to taste, pour in 150 ml white wine vinegar and leave to stand for ten minutes. Transfer the cooled mixture to a sterilised container, seal immediately and refrigerate. Experiment with different types of vinegar and spices.
Sources: Ambiente chefs, Marie B. Svobodova, Seriouseats.com, Great British Chefs, Food and Wine
