Ripe And Ready To Can

Preserving Tomatoes

(Originally Published December 11, 2008)

When I was growing up there were only 3 colors for tomatoes.  One was green, and that meant the tomato was not ripe and ready to eat (we did not do fried green tomatoes in my family, but I do love the dish today), the other was a sort of pinkish green, which meant the tomato was ripening, and at this stage it was commonly used in salads.  The final color was a deep red, which meant they were fully ripened and delicious.  As a child, growing up in Cleveland, I never had the pleasure of enjoying ripe green, yellow, orange, speckled, purple...or for that matter any other color tomato.  It was not until I became a  chef that I discovered yellow tomatoes.  It was not until I moved to California that I discovered all the other tomato colors and flavors.  This was the closest thing to culinary heaven I had ever seen.

Californians, and especially Northern Californians, take their tomatoes very seriously.  It is almost like a religion.  I have met “tomatophiles” who will not touch anything except a genuine heirloom tomato.  Others (such as me) are not so adamant about pedigree, and enjoy hybrid varietals just as well.  In fact, some of the hybrid tomato “mutts” are absolutely delicious, and particularly good for preserving.  What is especially wonderful about the whole California tomato experience is that during the peak season (early July to late October) you can find a dizzying variety of vine ripened and succulent examples to enjoy.  If you ever have the opportunity to go to Berkeley, head over to Berkeley Bowl during tomato season to experience anywhere from 20 to 100 varieties in any given week.  It is a wonder to behold.

Unfortunately, tomato season must come to an end at some point, and we are then left with the bland, tasteless hothouse grown tomatoes found in the produce section of any grocery store any time of the year.  You know the ones I am talking about.  They are generally hard, perfectly shaped, pinkish in color both outside and inside.  They taste about as tomatoey as a cucumber does.  If we want any sort of semblance of tomato flavor, we must resort to canned tomatoes, which can be quite good, but do little to remind me of the joy of summer tomato flavors.  I therefore opt to can my own tomatoes in the form of a cooked “passata” of sorts.

Passata is an Italian term which generally refers to tomatoes which have been cooked and canned or bottled.  There are several different methods for doing this, depending on who you talk to.  Some will briefly cook the tomatoes and then drain off some of the water utilizing various methods.  Others will cook the tomatoes over a longer period of time, reducing out the water.  Still others will merely cook the tomatoes long enough to soften the flesh, puree them, and then can or bottle them.  This last method is my preferred method, since it retains most of the original natural tomato flavor with minimal effort.  Overcooking tomatoes tends to kill most of the flavors found in fresh, ripe fruit.  The resulting sauce from a long cooking process can be delicious (and usually is), but the nuances of the fresh tomato vanish after as little as an hour on the stove.  I happen to like the slightly green, grassy, earthy flavors found in vine ripened fruit, and I have found that I can capture this quite well with a little thought and effort.  My friends and family appreciate it as well.

So what is it that I do, you ask?  Well, I am going to tell all.  The first thing you will need is to set aside some good canning jars, bands, and lids.   Canning supplies can be found in nearly any grocery or hardware store.  For each 25 pound case of tomatoes you will need approximately 7-1 quart Mason jars, along with 7 lids and bands (bands and jars are reusable, lids are not).  Start by getting these items together and setting them aside.

Next, and most importantly, you will need to source some good tomatoes.  The good news is that there are many places to get great tomatoes during the season.  The bad news is that the grocery store is generally not one of those places.

I am reminded of the time I went to an “industrial” tomato farm in Florida (which is a huge tomato grower), and watched as the workers picked tomatoes and loaded them onto the trucks for shipment.  What surprised me is that they picked them while they were green, and literally ignored any that were turning red.  When I inquired about this preposterous act, I was informed that if they pick them too ripe, by the time they get to market, they are generally either crushed or rot soon after making it to the shelves.  Grocery stores, as it turns out, want what they refer to as “bulletproof” tomatoes.  Those are the ones that, as previously mentioned, all look the same and are blemish free, tasteless, and have an incredible shelf life.  As you know, tomatoes will continue to change color and “ripen” as time goes on.  Unfortunately, a tomato which is picked green may turn red, yellow, or whatever other color it is expected to be, but the flavor and texture will no longer properly develop once it is picked.   It will get a bit softer, more colorful, and even a bit sweeter, but it will never taste like a vine ripened tomato.  Most grocery stores are now carrying some type of tomato on the vine (clusters of tomatoes still attached to the vine) which are indeed a bit better in flavor than most industrial tomatoes, but these are generally hothouse grown and lack the earthy qualities found in a proper dirt grown tomato.  No matter how you slice it, a grocery store tomato is truly a crapshoot at best.  You can get lucky, but there are easier ways to great tomatoes.  Let me tell you what I do.

Northern California is home to an incredible number of local farmer’s markets.  During tomato season you can find one almost any day of the week, and certainly on weekends.  Nearly every city in the world has its share of farmer’s markets as well.  This is one of my sources for tomatoes.  The other source is home growing.  The final source is my neighbors.  Tomato vines, as anyone who has grown then can testify, are quite prolific producers given the right conditions.  Summers in Livermore, CA (my home) are ideal for tomatoes.  This leads to enormous quantities of fruit from my garden and from my neighbors’ gardens as well, and we all like to share.  The local farmer’s market also gets very overloaded with tomatoes, and when the supply is large, the quality goes up and the price comes down.  That being said, there is a best time to buy tomatoes for the purpose of preserving, and that is towards the end of the season (late September to mid-October).  The reason for this is based on science.  Tomato vines create fruit for the purpose of reproduction.  That is the tomatoes’ only reason for existence.  The longer the fruit stays on the vine, the more mature the seeds become.  Years of genetic evolution has led to plants which know that the more delicious the fruit is (i.e. more sugar), the greater the likelihood that the tomato will be eaten, which is one way the seeds get spread.  The other way is to fall to the ground and split open, and this is facilitated by a softening of the flesh, which is also a result of sitting on the vine. As the tomato season draws to a close, these “late harvest” tomatoes start making their way to the market in larger and larger numbers.  Unfortunately for the growers, this means that they have to sell them quickly, because at this stage they have very little shelf life.  In fact, a large number of these tomatoes are damaged on the way to the market, and you can see tomato vendors culling these from their stock at any farmer’s market.  That is when I, the tomato vulture, swoop in for the kill.   This is indeed the one secret I am sharing at my behest.  I simply go to these vendors and ask them if they have any overripe or blemished tomatoes at a good price.  At least 5 out of 10 will sell you an entire 25 lb. case for about 1/4 the price (or less) of the tomatoes on display.  What is stunning is that these bargain tomatoes are IDEAL for preserving.  Yes, they are BETTER than the ones on display.  They are fully vine ripened, soft, and sweet as honey.  I generally buy between 2 and 4 cases.  Because red is still the most popular color for tomatoes, that is mostly what you will find.  I do also find other colors (green, yellow, purple, orange) and will buy these as well.  Just make sure they are ripe.  Once these are cooked in a batch of predominately red tomatoes the sauce will be red.  It is the “dominant” color.

Once I get these home I pour them into a sink of water and wash them.  If any appear to be truly rotten, I compost them.  I also sort out the ones which are perfectly good for a day or two of consumption in salads, etc., as there are usually a few pounds of these among the “rejects” from the market.  Once washed I use a small pairing knife to remove the green part which was connected to the vine, and I cut them in half and squeeze the seeds out into a colander placed over a bowl.  The seeds, as I have discovered, have a tendency to impart a bitterness to the tomatoes when cooked.  Some choose to leave them in, but I remove them.  The remaining tomato is set aside for cooking.  Once I have seeded all the tomatoes, I strain the juice and pulp from the seeds, as this has a lot of flavor.   I put the strained portion in a large pot and slowly reduce it to thick slurry by boiling over low heat, skimming any foam off the top.  Once this is the thickness of tomato sauce, I divide the prepared tomatoes over several large cooking pots and then pour a proportional amount of the juice slurry over them.  At this point I sprinkle a small amount of kosher or sea salt over the tomatoes and start cooking them slowly.  It is important to use low heat and be careful not to burn the tomatoes.  Once again, skim off any foam and cook them for no longer than about 15 to 20 minutes (once they have reached the boil).  You are not trying to make sauce at this stage, you are just prepping the tomatoes for canning.

While the tomatoes are cooking, it is a good idea to wash your canning jars, lids, and band.  I like to use my dishwasher, but you can do this by hand as well.   After you have washed these, prepare a pot of boiling water for the bands (do not boil the lids).  The bands can be put in the water to boil.  Once they have boiled, remove the bands from the heat and drop the lids in the water.  At this point you should only use tongs for handling the lids and bands (or you can get a nifty magnetic band and lid tool where you buy your canning supplies), and do not handle anything without sanitized hands.

Back to the cooking tomatoes we go.  Once they have softened from the gentle cooking process, remove them from the heat.  At this point it is now time to separate the skins and any remaining seeds from the pulp and juice.   The best way to do this is by using an old fashioned hand cranked food mill.  You can find one in most cooking stores, or on the internet.  I bought a good stainless steel one on eBay for about $20.  You can use a strainer, but it will take you a very long time to get all the pulp this way.  A food mill is the way to go.  Simply place the food mill over a suitable catch basin (a bowl), ladle the cooked tomatoes into the food mill and crank the handle, allowing the pulp to fall through to a bowl.  The skins and seeds can then be composted.

Tomatoes In A Food Mill

Once you have your juice/pulp mixture, stir it very well to evenly distribute the juice and pulp, as the pulp will tend to settle to the bottom of the vessel.  Fill the canning jars to approximately 1/2 inch below the top of the jar (you need this “headspace” to allow for expansion while sealing), and place a sterilized lid and band on top.  Let me emphasize this, DO NOT TOUCH THE LID WITH YOUR HANDS !!!  At this point it is crucial that you remain as sterile as possible, and your hands, even when freshly washed, are the equivalent of a bacterial rave.  Once the lid is on the jar you can place a band over it and you can use your hands to firmly snug the band down.  You do not need to muscle the band on this.  All you want to do is use it to hold the lid down at this point.  The sealing will be accomplished through a vacuum formed in the final procedure.  Just snug it up.

Now comes the part where you seal the jars for storage.  Properly sealed tomatoes will retain that delicious flavor you captured for about a year.  They will remain safe to consume for several years, if you are clean and if you seal properly.  After about a year, however, the acid in tomatoes tends to break down the tomato goodness, and the flavor and texture suffers.  Just make sure you use these up before the next season comes.

There are specific canning cookers available, but, as says the great Alton Brown of the Food Network, there is no need for single task items in the kitchen (except for a fire extinguisher).  A large cooking pot will do quite nicely, and I use the same one I cooked the tomatoes in.  Place a clean kitchen towel or several lavers of paper towels in the bottom of the pot, put your jars in the pot (this may take several batches, or you can use multiple pots), and fill the pot with enough water to cover the jars.  Bring these to a boil and boil them for 10 minutes.  Turn off the heat and let them cool a bit in the water bath.  You can also remove the jars from the bath immediately after the 10 minutes is up, but the boiling water can be a bit daunting.  As the jars sit an cool at room temperature, you will hear a series of “pings” as a vacuum is formed and the lids are sucked down to form the final seal.  This happens because the expanding gases in the headspace force their way out because hot gasses do not like to stay in small spaces. As the remaining gasses contract in the headspace the pressure inside becomes less than the pressure outside, and a vacuum forms.  Ahhh...the brilliance of physics!

Avoid any urge you may have to tighten down any loosened bands.  The bands serve almost no purpose at this point.  I say almost because the bands can be removed entirely, but they help prevent the seal from breaking because a slight blow to the edge of the seal could cause it to break.  The band helps protect this edge, and will also prevent massive spillage of contents in the event the lid breaks loose.  Tightening the bands could, in fact, break your precious seal.  Once the seal is broken, all bets are off as far as food safety goes.  If you look carefully at the top of your sealed lids (compare it to an unused lid for reference) you will notice that the center has a slight dip (on a new lid it is slightly raised).  This dip is assurance that your seal is intact.  If you ever notice any jars where this dip is raised, DO NOT EAT THE CONTENTS !   Canned food which is not sealed can make you very ill or even kill you.  If you have just canned the food, and there are any jars which do not seal, do not fret.  Rather than shelving the jar or discarding it, put it in the refrigerator and use it within the next several weeks, or use it right away.  The contents are still close to sterile, and will keep under refrigeration.  Label your sealed jars with the contents and the date of canning, and use your canned foods from oldest to newest (FIFO - First In, First Out). 

As these jars of preserved tomatoes sit, the pulp will settle leaving a little liquid juice at the top.  I pour this juice off after I open the jars, and store this “tomato water” in the freezer to use in soups.  It has a wonderful tomato flavor.  Before using a jar of tomatoes (or any food preserved by this method) I always check the seal for integrity, and give it a smell test when I open it.  If it smells off, discard it.  If you notice any gas bubbles in the food, discard it.  I am very careful and have had exactly zero spoilage incidents in many years of canning, so this is not a major problem as long as you are careful. 

The preserved tomatoes can be used as is for pizza.  I simply spoon a little onto my crust and add my toppings before baking.  For tomato sauce, I like to cook a little garlic, onion, basil, pepper, etc. in olive oil and then add my tomatoes.  I will cook this for about 30 minutes before using the sauce.  If you select the perfect tomatoes, and prepare them in the way, you and your guests will notice the difference.  There really is no comparison to anything else you can buy in a store.

If you want to make tomato paste salt the tomatoes a bit more before cooking them and when you have finished running the tomatoes through the food mill pour them onto a fine mesh sieve set over a bowl.

The sieve must be very fine (32 mesh or smaller) in order to allow the liquid (tomato water) to fall through without allowing the tomato pulp to fall through.  You can also use a very fine (and clean) window screen set over a sheetpan.  Set this outside in the sunlight and allow it to sit for approximately 6 to 8 hours, or until the tomato paste is a desired thickness.  You can save the tomato water for future use.

You may wish to loosely drape a bit of plastic wrap over the tomato pulp to avoid insects and dust from settling on it.  Once it is nice and thick you can scrape it off and store it in your refrigerator for weeks, or freeze it for at least a year.  It can also be stored in a jar and processed as you would for canning tomato puree.  This is so much better than any store bought tomato paste I have ever had, and can be used to thicken other tomato based sauces, or added to hollandaise sauce with some finely minced shallots to make a delicious Sauce Choron.

Fresh Tomato Paste

You really owe it to yourself to preserve your own tomatoes.  Your friends and family will all want to know the secret to your cooking, and it really just comes down to capturing the tomato at the peak of perfection. 

Enjoy in good health !