Tomatoes, pH, and Canning

I started canning tomatoes from my garden at least 10 years ago. Perhaps 11 or 12 years ago.

At the time I started, I did some research on the Internet and got comfortable with a method of canning that essentially requires the tomatoes to be boiled down and blended into a coulis or semi-sauce consistency (for at least 45 minutes, usually much more – for example, today, I simmered the tomatoes for 3 hours) and then pouring the cooked/blended liquid into sterilized jars with salt and a little bottled lemon juice. This approach puts boiling liquid into hot jars with boiled lids, but does not require boiling the jars once they’ve been filled.

Sometime in the interim, the English Internet got much more concerned about food safety with canning. For example, the USDA Guidelines on Tomato Canning state that all canned tomato preparations need to be processed in a water bath or pressure cooker (even if you’re dealing with a boiled preparation).

But, there are plenty of Internet resources in French and Italian (as well as a few in English) that still swear by this style of canning as what multiple generations of families have historically done with no problems.

After a few years of the annual debate about whether I needed to change my approach because the Internet says so, in this time of COVID-19 stay-at-home, I decided to buy a proper pH meter to figure out if my canned preparations were below the 4.6 pH cutoff of acidity, below which, C. botulinum bacteria cannot grow.

First, I ordered my new science toy. Then, I calibrated the pH meter according to the instructions. At first I thought it may be broken because the distilled water kept testing at a pH below 6 and I thought we all knew that water was supposed to be a pH of 7. Welp, turns out that’s true immediately after distillation, but when it sits around exposed to the atmosphere, distilled water absorbs carbon dioxide and becomes slightly acidic with a pH of around 5.8.

Relieved that my new toy wasn’t broken, I proceeded to test the pH of the raw tomatoes I was going to use to make the sauce — I took 3 samples for most of the tomatoes and there was some variance, even within the same piece of fruit. My pH meter is rated to be correct to within 0.01 pH. Here are the readings:

  • White Oxheart: 3.90, 3.83, 3.97
  • Snowberry: 3.90, 4.37, 3.96
  • Amish Salad: 4.39
  • Kentucky Beefsteak: 4.01, 4.15, 4.17
  • Golden Globe: 4.61, 4.86, 4.41
  • Isis Candy Cherry: 4.51, 4.37, 4.83

After 1 hour of boiling, the sauce tested at 3.96 & 3.99. After 2 hours of boiling, I used the stick blender to break up the remaining chunks of flesh and skins and tested the pH immediately after blending, where it measured 4.09 & 4.08.

Before Blending

After 3 hours of boiling, I tested the sauce and it measured 3.98 & 4.01. At this point, I was feeling pretty good. Since pH is a logarithmic scale. A pH of 4 is significantly more acidic than 4.6.

After 1 hour of boiling — pH of 3.96

For fun, I tested the lemon juice and it measured at a pH of 2.54 and 2.53. I put some lemon juice in each of the quart jars as well as some salt, filled the jars, and then stirred the mixture in each jar with a chopstick before my final pH measurement.

Final pH of 3.88

The five quart jars measured 3.95, 3.69, 3.88, 3.85, and 3.78. All well under the 4.6 danger point. So, I cleaned the rims, put the boiled lids on top, tightened the bands, and turned the jars upside down to cool. I am now very comfortable that the science supports my traditional no-water-bath approach to canning tomato coulis from my garden.

Too Many Cucumbers?


This picture doesn’t do it justice, but we’ve been getting almost equal volume cucumbers to tomatoes in every harvest this year.

Tomatoes are a gift that almost everyone appreciates.  They disappear like magic almost as soon as I start to complain that I don’t know what I’m going to do with them.

Cucumber, on the other hand?  Not so much.

This year, we’ve taken to conditioning gifts of tomatoes upon people taking cucumbers with them.

I’ve also researched cucumber recipes and tried to find more ways to use them.  I’m nowhere near the point where I need to be to take correct use of what my garden is producing.

I’ve seen this pattern in many of my start-ups.  They want to do X.  But it turns out, their business is used by others to do Y.  And now, they have to scramble to deal with the reality that is different than their plans.

Yet again, the garden is a great metaphor for start-ups.

It Keeps Coming

The harvests continue at a crazy pace.

The tomatoes, cukes and squash are going strong.  The okra and the eggplant are warming up and the tomatillo plant has decided to show off (see the basket in the back?  That’s from one plant).


In hilarious news, Thessoloniki decided to produce a little tomato-man.


In honor of his Greek roots, I’m calling him Dimitri.


A Hot Spring — When the Preparation Pays Off

Again, the Garden has great lessons for life.  As I wrote in April, this year, I did quite a bit of early preparation for the garden.  Sometimes, if you work hard, and conditions are just right, you get *really* lucky.  It looks like that’s what will happen with the garden this year.

Here are some of the tomato seedlings and a baby summer squash, immediately after they were planted back in late April.  Thanks to a warm weather prediction, I was able to get all the summer garden plants in the ground 2 weeks before I usually do (to avoid the frost).


Here they are a couple weeks later, after I added the supports.  (The pots contain hot peppers.)


Thanks to a very warm spring and the automatic watering system, I had the lushest June 1 garden I’ve every had.


The squash and basil were producing on the first of the month, so we could enjoy BBQ garden pizzas.



The cucumbers and butternut squash had a similar late spring.  Here they are after planting in late April.


And, here they are by early June (see them climbing the back fence?).


And this is what they look like today.  The cucumbers are producing like mad — I’ve had to resort to giving gift cukes to deal with the volume.  The butternuts are still too young to harvest, but if the early fruits are any indication, this fall should bring the biggest harvest of butternut squashes I’ve ever had.


And the tomatoes?  They are insane.  We’ve never had plants this big with this much fruit before the 4th of July.  We had our first ripe tomatoes on June 22nd!  What a great way to celebrate the first day of Summer (and yes, in an odd coincidence, it was overcast and drizzling that day).



Look at all those fruits just waiting to ripen in the sun!



The heat wave we are currently experiencing in California will only speed the rate of production.  Yesterday’s harvest was awesome — the last of the arugula that had gone to seed, and cukes and squash galore, plus one ripe pink caspian tomato and a few green tomatoes for frying.

I’m looking forward to a tomato-tacular summer!

Summer Bounty

After all the work and the waiting (we had a much more mild summer than normal, which delayed the tomatoes by almost a month), finally, the garden is in full production mode:


For the last several weeks, I’ve been harvesting a basket like this:


And this week, I expect there will be 2 or more.

The big downside to the late blooming garden is that much of the heavy harvesting will need to occur in September or October, when I’m working to close transactions for clients before the end of the fiscal quarter and/or traveling. But, the upside potential is huge as well. If we can avoid a frost, I have enough green tomatoes that there should be a constant stream of ripening tomatoes that stretches well into Thanksgiving. Making sauce and canning tomatoes and pickles in the cooler fall months is very much preferable to doing the same in August.

And the garden to start-up analogies continue: sometimes, despite your best efforts and hard work, things don’t scale when you plan them to scale. But, sometimes, the delay comes with its own sweet rewards.

Garden Prep

It’s almost that time of year again!

Back in January, I started seeds for tomatoes, peppers, eggplant, and okra.


The okra died. I restarted them a few weeks ago and they seem much happier.

Today, the garden is a sad dried out, over-grown and gone-to-seed collection.


The peppers had seed leaves by the end of January.


But the tomatoes, despite being planted several weeks later, have completely overtaken the peppers in terms of growth.


Just a bit of labor to harvest the remaining bits (yay beets!), then we turn the beds, add compost, fertilize, and it will be a welcome home to all of the seedlings that are thrilled at this weekend’s blazing sun.

Hurray for the coming summer garden!

A Northern Californian Summer Garden

The beauty of the first big harvest (even if it comes at least a month late due to weird 2011 weather!):


Even in a bad year, home-grown heirloom tomatoes are overwhelming in September:


Tomatoes are my favorite food, so many of my Summer meals look like this:


And when the harvests start to decline, it isn’t even all that sad:


Eventually, the summer garden plants need to be removed to make way for the winter garden. Ideally, I get a chance to do it before the first frost when there are still green tomatoes. This year, the last harvest of the summer was the week before Thanksgiving.


This is what happens when a Southerner marries a Californian with a garden (fried green tomatoes aren’t a side, they’re the main attraction in a dinner salad!).


And, of course, I pickled most of the green tomatoes for later enjoyment.


Last night, December 1st, we ate the very last of the ripe tomatoes from the Summer garden (stored in the fridge after the last harvest).


And now, it’s nothing but leafy greens, brassicas, and making our way through the winter squash ’til next summer.

The Latest Summer Garden

This year has been a doozy for Northern Californian gardeners. Winter was long. Spring was uncharacteristically wet. And summer seemed to lag by at least a month.

The result?

I didn’t have ripe tomatoes until after August 1st this year. Typically, ripe tomatoes are a July 4th treat and by the time August rolls around, I’m knee deep in tomatoes that need to be canned, dried, and gifted.

But not this year. The first real harvest of the year was the typical size, but it didn’t come until the second week of August:


And, the next week’s looked like a typical haul from the second week in July, not the third week in August:


Even the garlic bulbs were smaller than normal this year:


But, despite the late bloomers, we’ve finally started enjoying some of my favorite summer meals. Big salads of mixed veggies like this one (broiled eggplant, baked corn (a gift), baked squash, fresh red onions, fresh tomatoes, and balsamic vinegar and chevre).


Now that’s a summer garden treat.


As you may recall, I started late on the garden this year, and decided to minimize the plantings.

I am glad.

I started with this:


A few weeks later, had this:


And, now, after 3 weeks away with the garden on the automatic watering, I have more than enough work cut out for me:


Due to the late start and the cool summer start, I still don’t have any ripe tomatoes, but there are hundreds of green ones. And I can’t wait.

There are a few ripe cucumbers, and I suspect I’ll find a few other early goodies when I clear the weeds, prune the plants, and support the plants that have outgrown their allocated spaces.

Overall, I’m congratulating myself on the decision to downsize the garden this year. At the beginning, when the plants are small, it seems so easy to add just one or two more. But now, when production is in full swing, I’m going to have several hours of work each weekend just to keep the plants healthy and bearing fruit.

The garden/start-up analogy is clear: Plan for growth at the start so that it doesn’t crush you when it comes.