Dear Diary,
Here’s a home process I use each year to put up lots of jars of tomato sauce to use through the winter. I’ll say up front that I do not waterbath for this method. There are rules I follow in order to can in this way, with the end result being a very acidic (pH less than 4.3), uniform tomato-only sauce into sanitized jars. Acidity and sealed jars are the protective super powers of this sauce against spoilage and botulism.
My Personal Rules
-Ingredients are just tomatoes. Ripe, but not overripe. Rinsed and quartered. Blemishes and cores cut out. This means no garlic, onions, herbs, spices, sugar or other vegetables. Adding ingredients other than tomatoes can make it less acidic, thus reducing its high-acidity super powers. The only other potential ingredients I may add, after the tomatoes have cooked down, are vinegar (helps lower the pH) or salt (does not affect pH but improves flavor).
–This is a blended, uniform, reduced-tomato sauce, not just jarred whole tomatoes. I reduce the raw tomatoes by cooking out excess water to about 35-40% of their raw weight. I reduce the tomatoes by cooking them down in one of these ways:
- Cooking down in a stock pot (I use one with a heavy bottom to prevent burning and without a lid) on the stove over medium-low heat, stirring every 30 minutes (takes about 4-6 hrs)
- Roasting in the oven in open trays, rotating the pans and stirring halfway through (fastest method; takes about 2-2.5 hrs at 450 deg F)
- In a slow cooker (like a Crock pot), on high setting, with the lid cracked to allow evaporation overnight (most hands-off method and can be plugged into a garage or protected porch so my kitchen doesn’t heat up so much; takes about 8 hrs)
For both the roasting method and the slow cooker method, after they have cooked down, I transfer to the stock pot in order to blend the cooked tomatoes into sauce with the immersion blender.
I blend the cooked down tomatoes in a stainless-steel stock pot with an electric immersion blender. Seeds and skins (chopped fine by the blending process) don’t bother me so I leave them in (though others may food-mill them out before blending). Having a blended sauce helps assures a consistent pH throughout the jar.
The pH of the sauce at this point is pretty low (acidic). The batches I’ve tested ranged in pH from 3.9-4.2. I have a pH meter kit at home which comes with 4.0 and 7.0 calibrating liquids. pH meters are readily available online. Food safety experts consider foods with pH below 4.6 safe against botulism.
-I ladle hot, bubbling tomato sauce into hot, sanitized glass mason jars, with sanitized lids and rims. I use my dishwasher in “Sanitize” mode to initially clean the jars. Then, about 20 minutes before I’m ready to jar, I put them in the oven at 200 deg. I boil water to pour over the lids and rims that I’ll use. I’ve found that name-brand lids and rims are better quality than knock-off brands from online. The blended sauce is simmering and bubbling hot as I ladle it into the hot, prepared jars, one at a time. I’s all so hot! Long sleeves and gloves help protect me from hot splatter.
I use a ladle and mason jar funnel to fill jars with just a sliver of head space. I wipe the glass lip with a clean paper towel, and cap with a clean lid and rim. I hand-tighten then flip the jars upside down to cool. Once they are cooled, after several hours, I check that the lid is sucked in and the jars sealed. I’ve found the jars to be shelf-stable at this point, as long as the seal stays air-tight.
And what do I do with the sauce then?
This tomato sauce is just concentrated, unsalted tomatoes. Here are my favorite ways to use it, especially in the winter, when I’m craving summer flavors and nutrients. I dress up the tomato sauce at meal prep time in these ways once I pop open a jar:
- Marinara for pasta or pizza- add salt, caramelized onions, garlic, basil, oregano, fennel seed, splash of red wine or anchovy paste for extra flavor.
- Chili base– add salt, pepper, cumin, chili powder, paprika, beans and browned ground pork.
- Tomato soup with buttery toast- mix equal parts tomato sauce, whole milk and chicken stock/vegetable broth. Add salt, butter and herbs to flavor.
- Salsa for homemade nachos- add salt, minced onion, garlic, lime juice, cumin and olive oil.
Breakdown
When I did the math on a batch this week:
~ 22.4 lbs of our farm’s whole heirloom tomato seconds
Trimmed down to:
~17.6 lbs of raw, quartered tomatoes
Which after roasting in the oven (spread out in 3 roasting dishes) for 2 hrs at 450 deg F, reduced down to:
~6.8 lbs sauce (so reduced to 39% of raw chop, by weight)
The reduced tomato sauce pH measured at 4.0 with my home pH meter. I packed the hot sauce into exactly 3 one-quart jars (which equals 6 pints).