Plum tomatoes are a small variety of this fruit and are normally oblong rather than round. When choosing ripe tomatoes, it can be helpful to check the color of the fruit's skin, as those that are partially green may not be ready to eat. You should also make sure the flesh is somewhat firm, and not mushy. This is because fruit that is too hard may not be ripe yet, but tomatoes that are too soft could be overripe. It can be helpful to look for signs of disease or bruising, especially if you plan on canning plum tomatoes.
You can normally identify plum tomatoes by their size and shape, as they are typically much smaller than other varieties. A typical plum tomato might be around 3 to 4 inches (7.24 to 10.08 cm) long and could be oval or pear-shaped. Fruit that is smaller than this could have been picked too soon, while tomatoes that are larger that normal might have been crossbred with another variety.
Most varieties of plum tomatoes are red, though some are yellow. Before you choose plum tomatoes, it can be helpful to look the fruit over carefully to check the color of it. If the tomato is fully ripe, it will not have any green spots on it, and it should be an even shade of red or yellow. Generally speaking, produce with darker skin is riper than those with lighter skin.
In addition to checking the skin, you may want to see how firm the flesh is. When you feel plum tomatoes, they should be slightly soft, but should not cave in easily when pressed with the fingers. If the flesh seems very rigid when you press on it, the fruit might not quite be ready to eat. In this instance, you may be able to place the fruit in a sunny window for a few days to allow it to continue ripening.
Many cooks choose plum tomatoes because they are an excellent variety for making sauces. If this is something you would like to do, it can be very important to choose fruit without any blemishes. Some signs you may want to look for include black or brown ulcers on one side of the fruit, or small green specks that cover the entire tomato. Crops that are split open could also be affected with disease, so these should be avoided as well whenever canning tomatoes