Mix the salt, sugar, allspice, and peppercorns into the measured water in a saucepan and bring to a boil. Let the liquid cool down completely to infuse.
Place the tomatoes and the other flavorings in a sterilized 2-1/2 liter (4-pint) preserving jar and pour over the cool infused brine.
Seal the jar and leave in a warm place in your kitchen (25° C/77° F) for one week, until the tomatoes start fermenting. Transfer to the refrigerator or a cellar, where they can be kept unopened all winter.