http://www.producepete.com/shows/tomato.html

Don't ripen tomatoes on the windowsill. Never put them in the sun to ripen. Just put them out on the counter, stem end up, in a relatively cool place--not right next to the stove or the dishwasher. Put on a little Frank Sinatra music if you want them to ripen fast. If you want them to ripen faster--well, you can always put on the Stones. Never, ever refrigerate--not even after the tomato is ripe

LOL

Ethylene gas will hasten ripening of tomatoes. That's how the commercial ones which are picked green are ripened.

Ethylene is produced by certain fruits as they ripen. The easiest thing to do is to place the tomatoes in a bag with a banana. The banana will provide ethylene.

Jim

Here is a link that might be useful: Ethylene Ripening

Remember tomatoes used in canning should already be firm-ripe when picked. If you ripen out of the sun the tomatoes may have a lower pH.

Carol

oh, rats... I really would have liked to try Annie's Salsa (or my chili sauce) with tomatoes which ripened to The Stones. LOL

I asked Elizabeth Andress this question before and she said it says "preferably" vine ripened. You can still can them as long as the vines were not dead or frostbitten. Of course, you must add the bottled lemon juice or citric acid in both water bath or pressure canned tomatoes.

> If you ripen out of the sun the tomatoes may have a lower pH.

Carol or anybody,

What pH do the tomatoes have to be? I'll bet many of us have & use pH meters.

And pH is rather puzzling. Take a cup of vinegar, messure it, add a cup of distilled water and measure again. Then try adding yet another cup water. Compare results.

jt

This comes from the Faculty of Agriculture Sciences, Food, Nutrition and Health University of British Columbia:

"The processing method and,in turn, the amount of heat required to ensure destruction of the Clostridia botulinum spores is primarily related to the pH of the food. The active acidity of a food has an important effect on the heat resistance of microorganisms and their spores. In general, cells and spores are most heat resistant at or near neutrality. An increase in acidity hastens killing by heat. Therefore, fruits which are high in acid,(pH below 4.5) can be safely preserved at 100 [degrees] C in a boiling water bath. As well, during storage, the acid in the food prevents any spores from becoming active and producing spores. Vegetables, on the other hand, are low in acid and must be processed under pressure to raise the boiling point of the processing water to a lethal level to destroy all spores that are present."

Linda Lou, I'll try to find the source for the info on tomatoes ripened out of the sun. It was one of the Extension services, but I don't remember which one. I know sometimes they differ from the NCHFP in their positions, being either less conservative or more.

Carol

I found it, but I should have refreshed my memory before posting originally. The comment referred to ripening green tomatoes, not tomatoes almost-fully-vine-ripe. Note the last sentence.

So the correct information is: "Do not attempt to can or process tomatoes that are overly ripe or damaged, and do not harvest tomatoes from dead or frost-killed vines. And do not ripen green tomatoes indoors for canning, the proper acidity may not develop."

It's still a point worth noting. Information is from University of Wisconsin - Madison Extension.

Carol,

I only measured 9 Sungold tomatoes and will try some more tomorrow. They ranged from 3.38 to 4.04 with the green and partially ripe being more acidic than the fully ripe. Not at all what I expected.

jt

I found a second source (I definitely need to clean up my files!) from University of Wisconsin Madison Master-Food-Preserver training, so I guess my memory is better than I thought:

"DonÂt can late season tomatoes ripened indoors." The problem with both this and not ripening green tomatoes indoors and then canning them is that I can't find a specific reason.

IIRC, soil composition and exposure to sunlight affect acidity, but I haven't yet found a specific document.

Green tomatoes are much more acidic and then acidity decreases with ripening, which is why firm-ripe tomatoes are preferred for canning of standard tomato recipes and why green tomatoes can always be subbed in any recipe calling for ripe ones.

What I can't figure out is you'd think a green tomato ripened indoors would be more acidic and thus safe for canning, yet the recommendation is not to use them. There's something counter-intuitive going on here, some unknown factor.

Speaking of pH, I was surprised to discover how low the pH of some tomato varieties is. North Dakota State has an extensive horticultural program. They mention these varieties:

"NDSU has done some studies on the acidity of tomatoes. The pH does vary, but mostly stays above 4.3. Some of the varieties that tested high for us (above pH 5.0) are health kick (5.04),vita gold (5.09), La Roma (5.08), Russian (5.09), super marzano (5.20) and classica (5.05)."

I also read somewhere that all paste varieties are lower-acid. Interesting.

I wish I knew more of the science of this stuff.

Carol

When I pick tomatoes that are slightly underripe, with a bit of yellow on them along with mostly red, they ripen well if I place them in a big paper bag and sit them on the floor. I don't layer more than about 2-3 deep though, as more than that, will mash them a bit. I have a few on the counter right now, for 3-4 days and they look ready to eat. Thats for both cherry size and big beefsteaks. A few more out in the garden are now at that stage, and I will probably pick those tomorrow too.