The Last of the Season’s Tomatoes: A Few Preservation Methods

So, had enough tomatoes yet?  Maybe you’ve had all you can take and can’t wait to pull those plants out of the garden, or maybe you’ll never be able to get enough and wish you could grow them all year.  Either way, it’s a fun and useful treat to be able to get that home-garden flavor when you need to use tomatoes in the middle of the winter.  Due to our elongated Summer season in the Central Valley, it’s not unusual to get ripe or ripening tomatoes right up to the cool-season garden transition, so if you haven’t been prepping tomatoes to save over Winter, it’s probably not too late!

If you’ve never tried canning before, the process is easier than it might seem, although it’s easier with a few pieces of special gear and a little practice.  Here are a few methods of preserving tomatoes that you can try without anything that isn’t already in your kitchen!

Freezing

This is one of the simplest methods to preserve your fruit.  You may want to consider blanching your tomatoes before freezing, which is the process of quickly heating and then quickly cooling them, which stops the enzymatic process of decay and keeps your fruit more flavorful and brightly-colored.  Blanching is easy: drop your whole tomatoes into boiling water for 60 to 90 seconds, then scoop them out with a perforated spoon and immediately drop them into ice water to cool.  However, blanching is not necessary for success.

They can be frozen whole, but cutting them into halves, quarters, or dicing them will help to save space in the freezer.  It also depends on how you’d like to use them later.  It’s tempting to blend them down into a sauce and freeze them, although this limits how they can be used later, so consider keeping them as large as you have room for.  Some prefer to remove the skin and the cores before freezing, but it’s not necessary.  You’ll also lose nutrients that way!

Packing the tomatoes into a ziplock bag is a preferred approach because it allows you to push out as much air in the bag as possible, which will prevent freezer burn.  Packing tomatoes into a container with a lid can work, but freezer burn is much more likely. 

Once the pieces are packed and the air is removed, lay the bags flat in the freezer.  Once frozen flat, they can be arranged in any way that makes the most sense for space.  And, an argument can be made that the tomatoes appear more appetizing when cleanly organized and not frozen into a shapeless mass!

Drying Cherry and Plum Tomatoes

Any tomato can be dried in an oven, but cherry and plum-shaped tomatoes (like Romas) lend themselves best to this method due to their lower water content.  Cherries shrivel to a small, useful size, and plum tomatoes have much more meat, which makes it easier to control how dry you want them.

This method is perhaps the simplest: all you need is a baking sheet.  Parchment paper can be cleaner and help prevent sticking, but is optional.  Simply cut tomatoes in half, lay them cut-side up on the sheet, and put them in the oven at 250 degrees.  Many prefer to keep the oven door slightly ajar, to help with venting the evaporated moisture, and to keep an eye on the process.  

Cherry tomatoes will shrivel to small curled pieces; you can dry them until crisp if preferred, but pay close attention (and sample one occasionally) if you want to catch them while still soft or with that chewy, “sun-dried” texture.  You can remove plum tomatoes at any point in the process, but be careful with scorching if left in for an extended period.  Once again, sample them at different points for preference, or remove groups of them at different stages of dryness to use them for various purposes!  

Of course, the dryer the tomatoes, the longer they will last; if most of the water content is removed, dried tomatoes can last in the fridge for weeks, or you can pack them in olive oil for even longer preserving.  They can also be frozen, of course!

Fermenting Tomatoes

This method provides incredible, unique flavor, and is a great source of beneficial probiotics, which are essential for immunity and digestive health.  Lacto-fermentation is the process by which food is submerged in salty water, killing harmful bacteria and promoting the growth of useful lactobacillus bacteria, which thrives in a submerged, anaerobic environment.  Lactobacillus consumes naturally-present sugars in fruits and vegetables, converting it into lactic acid, which preserves flavor and nutrients and keeps the environment free of the bad stuff.  Fermentation is as old as human civilization itself, and it’s incredibly easy to do!  You’ll need salt, filtered water, a glass or ceramic jar (with lids), and perhaps a fermentation weight (read on).

Cherry tomatoes work great, and larger tomatoes like Romas and slicer tomatoes will also do just fine, although you’ll need bigger vessels for those as it’s best to keep the tomatoes whole.  Cutting them and exposing the inner flesh will cause them to get too mushy over time.  Rinse your tomatoes, and wash out your vessels with hot, soapy water.  Glass jars and ceramic dishes with lids are best; avoid plastic and metal.  In addition to the tomatoes, anything can be added to the jars: garden herbs, pepper, garlic, onion slices, etc.  Feel free to mix it up.

You’ll want to use filtered water and unadulterated salt, like sea salt, rather than table salt with additives like iodine.  A little salt goes a long way, but a good ratio is 1 tablespoon of salt for your average 16oz canning jar (like your standard Ball or Kerr jar).  Increase the amount based on the jar size for larger tomatoes.

Add the salt and a little filtered water to your clean jars first, and mix it up to dissolve the salt.  Then pack your jars with tomatoes, as full as possible without squishing them.  Once full, fill the jar with water to the brim so that all tomatoes are fully submerged.  A fermentation weight can be useful here, which is a small, round, thick piece of glass designed to sit at the top of a jar and keep food from floating above the surface.  These can be purchased cheaply online or anywhere you buy canning materials.  People have used other items as well, like a small stone that has been boiled to be sterile.  It may not be necessary to weigh down the tomatoes depending on how they’re packed, but keeping everything submerged is important to make sure your tomatoes remain sterile.  

Once submerged, apply a loose-fitting lid, as the fermentation process releases gasses and can sometimes cause bubbly water to spill over the side.  This is more common with tightly-packed veggies like sauerkraut and kimchi, but can happen with tomatoes.  Make sure the lid is tight enough to keep out dust, but slightly loose to allow gas to expel.  Just screw it on a couple turns and it should be fine.

And now it’s off to the races!  Keep your jars at room temperature out of sunlight, like in a corner on your kitchen counter, or even on an empty pantry shelf.  There is no minimum for the fermentation time, but giving it an initial 5 days is a good start.  You can leave it fermenting for 3-4 weeks if desired; keep an eye on the appearance of the tomatoes, and feel free to sample them to know the flavor and texture changes.  Once you’ve decided that it’s been long enough, tighten the lid and put them in the fridge, which will slow the fermentation speed considerably, keeping the tomatoes in their current state for much longer.  Fermented tomatoes can last for months when kept cold, make a great sauce when blended, and add a bright punch in a salad or sandwich.  Or, just eat them straight out of the jar!