Slow Cooker to Freezer…and Back Again

Canning tomato sauce can be tricky business, especially if you’re inclined to add peppers and onions for a ready-made spaghetti sauce. Because the acidity of tomatoes and their sauces are just on the border of being suitable for water bath canning, extra veggies can add up to a sauce that is not shelf stable. Not to mention that peeling tomatoes and cooking down the sauce can take a lot of hot, sweaty hours in the kitchen when you’d rather be enjoying a chance to breathe now that the kids are back in school. Good news: you can make your tomato sauce in a slow cooker, freeze it, and then use the slow cooker again when you feel like tomato sauce for dinner. We’ve pulled out some great tips from Smitten Kitchen, Adventures of Valley Writer and added a few of our own to help you get the best sauce for your time and effort.

The tomatoes, ready to go
The tomatoes, ready to go / Susan Fitzgerald / CC BY 2.0

Cook the whole tomato. After washing the tomatoes, coring them and removing any leaves, halve (or quarter) the tomatoes and dump them in the slow cooker on low and walk away for at least 4-5 hours.

What about the skins and seeds? We know, we know, no one likes to get icky bits of skin in their teeth. But who likes peeling tomatoes either? Even with the blanching method, it’s hot work for a large batch. Once your tomatoes have cooked down, use an immersion blender to smooth the sauce.

No, seriously, my kids won’t touch it with any seeds in it. No problem. Pull out a mesh strainer and push the sauce through to catch just the seeds and any last tough bits. You’ll have gotten the absolute most out of your tomatoes, but no one will have to pick around seeds.

Portion, cool and freeze. Never put a large, hot mass into your freezer. The sauce will end up hovering at an unsafe temperature for too long and will threaten to bring already frozen foods into the temperature danger zone. Instead, portion your sauce into containers (leaving at least an inch of headspace to allow the sauce to expand as it freezes) and allow the sauce to cool, unsealed, to room temperature. Then you can seal your containers and freezer your sauce for later use.

Make a miraculously easy meal. When you need tomato sauce, pull some of your sauce out of the freezer and defrost in the fridge overnight. The next morning, pop the sauce into the slow cooker on low, spice it according to a healthy recipe like Spaghetti with Turkey Meat Sauce (3 Guiding Stars), and enjoy a relaxed dinner when evening rolls around.