Too Many Tomatoes? Time to Make Passata

Great tomatoes are the reward for getting through the sticky, humid days of mid-summer. This time of year, tomatoes are everywhere — striated heirlooms at the farmer's market, quarts near-overflowing with compact grape tomatoes at the grocery store, and abundant beefsteaks glistening in the sunlight in the garden. It's a glorious time for tomato appreciators, but it's all too brief. It seems unfair that one of the best produce items for cooking happens to be in season at the exact time that turning on the oven is the least appealing.

If you find yourself with too many tomatoes on your hands, and a hope to preserve some of that umami juicy tomato flavor for months more lacking in that abundance, there's a simple solution: Make tomato passata.

Passata, if you're unfamiliar, is tomato puree. It's not a tomato sauce — there's not anything in it aside from tomatoes, a few sprigs of basil, and some lemon juice or citric acid to help with preservation. It's a great way to reduce a lot of tomatoes into to a cooked-down puree that you can use for months after tomato season has passed, thanks to the magic of canning. Here's how to do it:

Score your tomatoes

The thing about passata is that it requires a whole lot of tomatoes. Our recipe calls for 50 pounds of plum tomatoes to make six quart-sized jars of passata. That's a good quantity, so look for deals on peak tomatoes from CSAs, friends with overabundant tomato plants, or the farmers market, where less aesthetically pleasing tomatoes, often called seconds, are sometimes sold at a steep discount.

Give them a brief boil

Once you have your tomatoes on hand, fill two large stockpots with three inches of water and divide the tomatoes evenly among them. Add 1/4 cup of kosher salt to each pot and bring to a boil, cooking the tomatoes until tender, 20 to 30 minutes.

Puree the tomatoes into passata

Strain and cool the tomatoes for about half an hour before you make your homemade puree (allowing them to cool briefly helps you to avoid hot tomato splatter). You're going to want a device to help break the tomatoes down and partially remove their seeds and skin. You can use an electric sauce maker if you have one, but if you don't want to acquire one of those, a hand-cranked food mill will work here, too. You can also use a Kitchenaid stand mixer with the fruit/vegetable strainer set if you have it. Technically you could push the tomatoes through a coarse strainer or colander, but it would be pretty onerous.

Prep the canning jars and (briefly) simmer the passata

Now you'll want to make use of your two stockpots again. In one, prepare the six glass quart-sized jars (like Mason or Weck jars) for canning: Put them in a stockpot lined with kitchen towels (to prevent the jars from knocking against the bottom of the pot and to prevent heat shocks), fill the stockpot to cover the jars by an inch, and bring them to a simmer. Keep the jars in simmering water until you're ready to fill them.

In the other stockpot, bring the puree from the tomatoes that you strained through the food mill or sauce maker to a simmer, then stir in the citric acid to help preserve the passata. Take the puree off the heat and you're ready to can.

Fill and process the jars

Following proper canning protocol is crucial to avoid the growth of bacteria and unpleasant toxins, so this part is best done with care. Use heat-proof gloves or a jar lifter to remove the jars from the simmering water one at a time, and fill each of them with a sprig of basil and the passata (a wide-mouth funnel is especially handy here), leaving a half inch of headroom at the top of the jar. Pass a small spatula around the sides of the jar to remove any air bubbles that may have formed, then screw the top of the jar closed. Once you've ladled the passata into all the jars and sealed them, carefully lower the jars back into the stockpot of simmering water, making sure they're covered by an inch of water. Then boil them for 45 minutes to form the vacuum seal.

Test the seal

Once you're done, you'll have six jars of tomato passata that will last up to a year. Make sure the seal is set — the top should be slightly concave, and be able to stand upside down without any leakage. Open one in a few months, when the days are shorter and the tomatoes are once again wan and of the greenhouse variety, and you'll swear it's August all over again.