According to conventional wisdom, you should always buy paste tomatoes (such as Romas) for canning. The reason given is that paste tomatoes contain less moisture, and so take less time to boil down to a thick sauce. Also, you’re paying for tomato flesh, rather than sauce.
So how true is this conventional wisdom? We decided to find out.
After our first tomato buy this year, I ended up with about a hundred and twenty pounds of tomatoes. About half were cases of “mixed heirlooms” from Art Heinneman. The heirlooms were beautiful, and represented a variety of different flavors. Of these, we ate about 20 pounds fresh, slicing them on sandwiches or into salads. The rest, we canned.
The other half of our boxes contained San Marzano paste tomatoes. San Marzanos are actually an heirloom paste tomato, famous for having a rich, deep almost chocolatey taste. But I tasted none of that richness in these tomatoes. I assume the flavor referred to is in the sauce, rather than in the fresh fruit. Because compared to the heirlooms, I found them incredibly bland and tasteless. My 3-year-old daughter Luella however showed no such scruples.
It’s clear the mixed heirloom tomatoes from Art had vastly superior flavor for eating fresh. And you can tell, just from biting into these tomatoes, that the paste tomatoes had lower moisture content. So does the economic advantage of those lower-moisture paste tomatoes outweigh the superior flavor of the heirlooms? Again, conventional wisdom suggests that for canning purposes, we should always choose paste tomatoes. But how true is that maxim?
I like a thick, cloying tomato sauce. I like it to cling to your pasta, almost like a paste. And so I boil my sauces WAY down. For every 10 pounds of heirloom tomatoes, I got 4 pints of sauce. For every 10 pounds of paste tomatoes, I got 4.5 pints of sauce. That means you get easily more than 10 percent more sauce from paste tomatoes.
The difference becomes more apparent when we cold-packed tomatoes with no added water. In this recipe, after putting 1/4 teaspoon of citric acid in each piping hot sterilized pint jar, you pack the hot jar full of blanched tomatoes, squish them down to eliminate air pockets and then put them in the hot-water bath for 85 minutes.
During processing, the solid tomato flesh separates from the water and floats to the surface. The resulting jar looks something like a black-and-tan, and makes it easy to discern exactly how much more water is in the heirlooms. Again, the paste tomatoes appear to easily contain at least 10 percent less water.
If you’re performing a strict economic calculation, paste tomatoes give you at least 10 percent greater value (in tomato flesh), and probably also take about 10 percent less time to boil down. That’s a significant savings.
But what about taste?
Heirlooms taste better, and I haven’t decided yet whether heirlooms result in a better-flavored sauce. Certainly the bland flavor of our San Marzanos improved dramatically when sauced. But the heirlooms were outstanding. I haven’t tasted the sauces next to each other, and now I may never know, as my jars of sauces from the two types have become hopelessly confused. But as we open a jar of tomato sauce every other week this year, I’ll taste carefully, looking for that extra something.
Because my sauces are so extremely thick, I consider one of my pint jars to be the equivalent of a quart jar of tomato sauce from the grocery store. A jar at the grocery store might cost anywhere from 3 dollars to 6, depending on its quality, whether it was organic, and whether it was on sale. I paid $42 for most of my 20 pound boxes of tomatoes, both paste tomatoes and heirlooms. These were essentially wholesale prices, as we purchased large quantities of these top-grade tomatoes directly from the farmer and sold them to friends and neighbors without markup in one of our annual Bulk Tomato Buys. For the paste tomatoes, the cost works out to: $4.60 per jar of sauce. Yikes! For heirlooms, that works out to: $5.25 per jar. Double yikes! So this was not a money-saving venture, either way. The quality of my sauces is WAY higher and I know they’re free of unnecessary chemical ingredients, such as the thickeners they use in commercial sauces to get more sauce out of less tomatoes. I know the farmer who provided my tomatoes, and I love the way he farms. But when I go through all this work, I’d still like my sauces to be cheaper too!
One of the 20 pound boxes I picked up were #2 heirlooms. That #2 grade means they had too many blemishes to be sold in a supermarket. These I picked up for a mere $22 a box, and got the same yield as the heirlooms. That works out to $2.75 a jar. That’s a much better deal!
In the end, the debate about whether you get more value from heirlooms or paste tomatoes appears to be a bit of a wild-goose-chase. This discussion distracts us from the most obvious savings. For the most value, I should be buying all #2 tomatoes! The blemishes don’t matter when you’re canning them. So long as you can can them within a couple of days (beyond this, those blemishes turn to rot) you’ll be fine. Whether they are #2 heirlooms or #2 paste tomatoes makes but a small difference to your pocketbook. The important thing is that they’re #2!
A secret that will save you time
Now that you know which tomatoes will give you the most sauce for your money, let me leave you with one tip that will cut down on your time commitment dramatically.
After cooking 10 pounds of tomatoes for a little while, place the tomatoes in a food mill or colander and let the clear liquid drip back into a pot. Once most of the liquid has drained out, place that pot on the stove and blast it with heat, stirring constantly. With no solids to worry about burning, you can reduce that liquid to a syrup in no time at all. Give it a taste: it will taste like a cross between tomatoes and chocolate. Then, mill the tomatoes right into this syrup, removing the seeds and skins. Once you stir them back together, you’ll have a huge jump start on the long job of reducing a sauce. I discovered this method on my final batch of sauce. So I’ll have to wait to enjoy the labor savings until next year!