How to Can, Freeze, and Preserve Tomatoes
The summertime flavor of just-picked tomatoes is frustratingly fleeting. Unless, of course, you preserve your garden crop or farmers market haul. There are a number of methods for doing this, including drying, pickling, and boiling them down for jam. But if you're looking to enjoy the flavor or a sun-ripened tomato come December, your best bets are canning and freezing. Here are some simple how-to's and ideas for making your tomatoes last.
How to Can Tomatoes
Generally, there are two ways to can tomatoes: with a pressure canner or without one.
It's important to note that a pressure canner is a different piece of equipment than a pressure cooker. Because a pressure cooker heats and cools so quickly, it's not safe to use for canning. To determine whether you have the right appliance, check for a dial or weighted gauge. Pressure canners are usually also bigger than pressure cookers, but that's not a sure test.
When working with a pressure canner, first wash your tomatoes. Then briefly boil them until their skins split; shock the tomatoes in cold water. This will allow you to remove the tomatoes' skins and cores before jarring them; you can also halve, dice, or stew them before canning.
The USDA recommends adding two tablespoons of lemon juice for each quart of tomatoes to prevent spoilage; you might also choose to add a teaspoon of salt and a basil leaf to each jar.
Without a pressure canner, the method starts the exact same way. Except in this case, rather than insert the jars into a dedicated contraption, you'll use a stockpot filled with water; the jars should be submerged at least two or three inches before boiling. Check the USDA website for the appropriate boil time for your location (it's based on elevation), but plan on dedicating at least an hour to the heating portion of the project.
How to Freeze Tomatoes
There's one drawback to freezing raw tomatoes: They tend to lose their sturdiness behind the freezer door, so it's impossible to thaw your way back to a satisfying tomato sandwich or Greek salad. But if texture isn't an issue, freezing is by far the simplest way to extend your tomatoes' lifespan.
To freeze raw tomatoes of any size, including cherry tomatoes, start by washing the tomatoes and trimming their stems. (Resist the urge to salt or otherwise season the tomatoes, since a stay in the freezer will weaken or strengthen the flavor, and the results are apt to be unpleasant.) Then place the tomatoes on a baking sheet and freeze. That's it. No blanching required. Once the tomatoes are frozen, transfer them to freezer bags.
When you're ready to reconstitute a frozen tomato, run it under warm water: The skin will slip off. But if you'd prefer to deal with the skin removal process prior to freezing, just boil and shock, as if preparing them for canning.