Drying and canning are always options, very good ones that should be used. There is another ancient method of preserving the bountiful harvest to capture the fresh flavors for the cold winter and gray early spring months when there wasn’t much of anything fresh available. Fermenting fresh vegetables opens up so many flavors and paths to storing this summer’s bounty for the coming winter. We will look at one such method that not only ferments the over-abundance of tomatoes, but concentrates their flavors as a bonus.
A word about fermenting before we begin is in order, so that you don’t come home one day and throw out the entire project due to a misconception or lack of understanding of how the process works. This particular process uses a wild fermentation, meaning the combination of wild airborne yeasts and the naturally occurring bacteria that is on the tomatoes. This wild fermentation is spontaneous; you don’t do anything to help it along. The acid in the tomatoes provide the perfect environment to support lactic acid fermentation. There will be a surface mold which is white and completely normal. Indeed, the white surface mold is needed to protect the tomatoes from rotting. You should not see any colored mold or offensive “rotting” odors.
This process has been used for several hundred years in Italy; probably the first time was shortly after the tomato made its way from America to Italy in the early 1500s. It is still being used today, all across Italy, as small scale home growers put up their harvests to have the flavor of summer to remember during the coming winter.
The beauty of this method is that it is very scalable, able to handle 20 lbs. in one batch and 100 lbs. or more the next one.
Start with all of the tomatoes washed, stems and any bad spots removed. Get a container that is larger than the amount of tomatoes, so that when all of the tomatoes are crushed there are several inches of space to the top of the container. If necessary, use more than one container. Crush all of the tomatoes and add them to the container. Stir well and cover with a towel, dishcloth or such to keep insects out while allowing air circulation.
The fermentation happens within a few hours and bubbles will appear, with the solids coming to the top and a white mold forming on them. Remember, white mold is good! Stir twice a day, mixing in the mold.
The fermentation will take from 4 to 5 days, depending on temperature and then stop. Remove the solids from the top and strain the mixture through a strainer. One of the best ways to do this is by using a hand cranked device that separates the skins and seeds from the pulp, called a Squeezo or Roma food strainer. The Squeezo is all metal and more expensive but will last several lifetimes!
After straining, keep the pulp and compost the seeds and skins. (As a side note, it you are wanting to save the seeds from those wonderful tomatoes, just transfer them into another bucket for a second ferment for about a week, scoop off the mold on top and strain out the seeds. Rinse thoroughly and dry on paper towels with the seeds spread out.) The pulp will still have a lot of moisture that needs to be removed. Do this by further straining the pulp in a fine mesh bag or cheese making bag over the sink or a catch bowl. Tie the bag closed, let it hang and drip liquid for a day. It may become covered with a layer of white mold again, just “shave” it off after it finishes the drip process.
The pulp will be noticeably drier and reduced in volume. If the consistency is thick enough for you, stop here. If not, put the bag between two boards or plates with a weight on top to compress it and further drain moisture out for another day or two.
When it is the consistency that you want, traditionally that of firm dough, remove any mold on the bag, open it up and peel it off of the now-firm pulp. The Italians add 25 percent salt to the tomato pulp, but most Americans find this to be way too salty. 10 percent is a good starting point, as it is much easier to add salt than to remove it! Mix the salt in well and let sit. After a few hours knead the mixture just like dough to develop the texture and store it in a jar. It does not need to be refrigerated and will last for several months. In Italy it is usually stored in waxed paper. If you do choose to store it in the refrigerator, it should last for a year.
The end result will be a preserve that is about 8 – 10 percent of the amount of tomatoes you started with. The flavors will be highly concentrated, so a very small amount will add a tremendous amount of flavor to your dishes, from soups, stews and sauces to omelets, dressings and marinades.