Herewith begins my contribution to the Tigress Can Jam! If you’ve missed it, the canjam is a yearlong canning challenge. Each month, canjammers will be asked to create a water-bath friendly recipe based on a seasonal ingredient. Tigress started us off gently, with citrus. I assumed—rightly as it turns out!—that this would turn into a [...]]]>

Herewith begins my contribution to the Tigress Can Jam! If you’ve missed it, the canjam is a yearlong canning challenge. Each month, canjammers will be asked to create a water-bath friendly recipe based on a seasonal ingredient. Tigress started us off gently, with citrus. I assumed—rightly as it turns out!—that this would turn into a giant marmalade fest, so I was looking for something just a little bit off-center. I found my inspiration in the freezer: a bag of sugared strawberries I put away last May. Technically, I guess that means I’m in violation of the seasonality rule, but given that these were local berries that I picked and stored myself, I hope you’ll agree that it’s in the spirit of the game.

I *love* the way this turned out. I started with a recipe in the Ball Blue Book, but reduced the sugar (I wanted it tarter), added more lemons, kept the peels, and eliminated the pectin…which makes it not really a Blue Book recipe at all. It’s more in the spirit of the tangerine marmalade I made last month, but with lemons and strawberries instead. Now, if you do the Twitter Thing, you’ll know that sugar has recently been a subject of much controversy. I tell you, people: yes, you can reduce the sugar in a marmalade. The safety question in water-bath canning is about acid. Lemons and strawberries have plenty of acid. As both the National Center for Home Food Preservation and the Ball Corporation’s Fresh Preserving Guide make clear, it is not a safety issue to reduce the amount of sugar in fruit preserves. Now, this is not to say that sugar isn’t a preservative—it is, my friends, it is!—but preservation is fundamentally a different question than safety. Sugar preserves taste and helps you get to the gelling point faster. It also prevents mold, which is why jams and preserves that are high in sugar will last longer once you’ve opened them. Sometimes low-sugar preserves aren’t as pretty as high-sugar preserves, and they often have a softer set. Some people, such as the USDA, say that you need to process low-sugar foods longer than high-sugar foods. (But keep in mind that the French don’t process their canned jams at all, and they’re still here.) In this case, though, there’s so much pectin in the lemons that I achieved an excellent set, without pectin and with less sugar than the recipe called for. And since the product is mostly lemons, it’s plenty acidic.

Tweaking canning recipes is a topic that gets plenty of food educators exercised. Those who object are, quite rightly, concerned about your safety. There is a growing consensus among some in the “new” canning community, however, that some of these rules are a tad too rigid. The spirit of the canjam is to improvise within the limits of safety. Part of the challenge of this exercise is to figure out what you can change (spices, fruit combinations, sweeteners) and what you can’t. If you change the recipe, there is, in fact, a chance that something will go wrong. Maybe your jam won’t set. Maybe it will grow mold in 3 months. But you know what? If you see mold, throw it out. Live and learn. And if you’re worried about botulism, don’t, so long as you’re working in a high-acid (i.e., fruit-filled) environment. My personal opinion is that the USDA rules should be taken as a guideline, not as hard and fast rules. Keep in mind that the USDA also recommends that you not eat raw fish or raw eggs, and that meat should be cooked through. Nevertheless, for the record, when you change a recipe, you are doing so at your own risk.

Now that that’s out of the way, let’s get down to business!

Strawberry Lemon Marmalade

1 qt frozen strawberries, in sugar
4 medium lemons, chopped
3 c. sugar
about 3 c. water

1) Wash your lemons. Slice them as thinly as possible, then chop them into pieces. Put them into your jam pot, cover with water, bring to a boil, and simmer 5 minutes. Turn off the heat and let the pan cool. Put a lid on the pan and walk away. Meanwhile, take your berries out of the freezer.

2) The next day, mash the berries and their juices (I use a potato masher). Toss them into the pot along with the sugar. Bring to a boil. Boil it until you’re just at the gelling point. Be careful: there at the end, it gets quite thick rather quickly, and my last jar is a bit thicker than I might like. There’s *lots* of pectin in the pith.

3) Meanwhile, sterilize 4 or 5 half-pint jars and bring your water bath to a boil. Heat new lids. Transfer the hot jam to the hot jars and adjust the two-piece lids. Process in a boiling-water bath canner for 10 minutes.

My version made 4 half pints and 1 4-oz jar, which I’m giving away! Leave a comment by Monday at 8 AM and I’ll select a winner by random number generator. Happy canning!

When you first asked me this, I thought it was an easy question. So easy, in fact, that I planned on conducting a little kitchen experiment to document both the reaction and its counter-reaction. But things didn’t work out that way, [...]]]> Sometimes garlic turns blue when I cook it. Why? Is it safe to eat?

(Andrew, Philadelphia)

When you first asked me this, I thought it was an easy question. So easy, in fact, that I planned on conducting a little kitchen experiment to document both the reaction and its counter-reaction. But things didn’t work out that way, as I’ll explain below. But first, let’s answer your question. The simplest answer is that garlic contains a set of pigments known as anthocyanins. Under certain conditions, the anthocyanins appear blue-green. They are harmless to eat, and may even go away depending on what you do to the dish next. Harold McGee explained his take on this in his inaugural “Curious Cook” column in the New York Times:

I hear every year from cooks who have been alarmed at seeing normally pale garlic turn bright green and even blue, sometimes when the cloves are pickled whole, sometimes when they’re chopped and cooked with other ingredients. I’d often been puzzled by little blue-green specks when I made garlic bread with loaves of sourdough, but I was really rattled the first time I puréed raw garlic, onion and ginger together in a blender to make chicken in yogurt from Madhur Jaffrey’s “Invitation to Indian Cooking.” When I fried the purée the entire mass turned turquoise blue.

I asked a couple of Indian friends who happen to be plant biologists whether they knew what was going on. They said they had never seen the blue purée, because Indian cooks don’t grind onions and garlic together. They grind or chop them separately and usually fry the onions first. . . .

According to chemists at the China Agricultural University in Beijing, aging the garlic gives it a chance to accumulate large quantities of one of the chemicals that generate the color; fresh garlic doesn’t green much at all. And a strong green color develops in Laba garlic only with acetic acid, the main acid in vinegar (also found in sourdough), because it’s especially effective at breaching internal membranes and mixing the cell chemicals that react together to create the green pigment. The pigment itself turns out to be a close chemical relative of chlorophyll, which gives all green leaves their color.

Two recent reports from the House Foods Corporation in Japan detail exactly how the garlic and garlic-onion pigments develop. Their creators are the same handful of sulfur compounds and enzymes that give the allium family its unique pungent flavors. Under the right conditions these chemicals react with each other and with common amino acids to make pyrroles, clusters of carbon-nitrogen rings. These rings can be linked together into multipyrrole molecules.

The ring structures absorb particular wavelengths of light, and thus appear colored. The two-pyrrole molecule looks red, the three-pyrrole molecule looks blue and the four-pyrrole molecule looks green, as does its cousin tetrapyrrole, the chlorophyll molecule. Like chlorophyll, all the pyrrole pigments are perfectly safe to eat.

Now, I was familiar with the explanation that says that the blue-green apparance is more likely to take place in acid environments. In my own experience I noted that garlic only tends to turn blue when cooked in lemon juice, usually in a metal pan. In fact, the anthocyanin/acid relationship is so strong that you can actually use some vegetables—the classic is red cabbage—as a home pH meter. (You can learn more about the chemistry of red cabbage color changes in this episode of Distillations, a chemistry podcast.)

It was with all of this in mind that I had what I thought was a brilliant idea. If acid turns garlic blue, shouldn’t baking soda, a base, turn it back? So for you, dear readers, I attempted to conduct a scientific experiment.

First I added lemon juice to minced garlic in a glass bowl. Nothing happened.
I transferred the contents to a metal pan. Nothing happened.
I heated it up, thinking maybe the reaction needed a jump start. Still nothing happened.
I added white vinegar, thinking maybe my lemons weren’t strong enough. Nothing happened.
We ate dinner, giving the garlic and acid time to get to know each other. Still no blue.

At this point, I did some additional research and learned that garlic actually turns blue for two reasons. Certainly the anthocyanins are the main culprit. But garlic also contains a lot of sulfate that, when combined with copper, creates copper sulfate, an insoluble, bright turquoise compound. (Again: still fine to eat.) Apparently the trace amounts of copper in water and other foods can be enough to trigger the reaction.

So, I added water. Still no blue.

More research: what food stuffs have high proportions of copper, I wondered? Leafy green vegetables, like kale, chard, and spinach, and certain nuts, like sesame seeds.

I dumped a big pile of sesame seeds into the pot and kept cooking. At this point the kitchen smelled terrible. But still no blue.
Table salt, perhaps, with its iodine content? No go.

This went on and on for about an hour before I finally gave up. So while I can certainly tell you what turns garlic blue, I cannot tell you whether you can turn it back by adding baking soda. If it happens to you, give it a try, and let me know.

3–4 lemons beaucoup de kosher salt more lemon juice a sterilized pint jar in [...]]]>
I love preserved lemons. They’re like a sour, citrus salt kick, ready to be eaten straight out of the jar or tossed into salads. They’re also very easy to make, but you have to be patient and trust in the anti-microbial powers of salt.

What you’ll need:

3–4 lemons
beaucoup de kosher salt
more lemon juice
a sterilized pint jar
in an ideal world: a plastic lid (I’ll explain why below)

What to do:

Take your lemons and make 8 or so longitudinal cuts. You want to go almost to the tips, but not quite, so they’re still connected. Do this over a bowl so you can collect the juice. Next, rub the cut flesh with kosher salt. I’m talking lots of salt here. Now stuff the lemons into the jar. (As an aside: it’s not clear to me why you have to sterilize the jar, seeing as how you’re rubbing your fingers all over the lemons and then have to smoosh them to fit. But all the recipes say to do this, so I’m just the messenger.) Pour the newly collected lemon juice, plus the juice from at least one other lemon, into the jar. It might not be full, but that’s OK: the lemons will release more liquid as they age. Screw on the lid.

Now you wait. Just sit it on the countertop, or in a cabinet, and let it ferment for at least a couple of weeks. If, after a few days, it isn’t full of liquid, add more lemon juice. If your house is cold, like mine has been, it might take up to a month before they’re done. Turn the jar upside down every once and awhile (and put a plate underneath it so it doesn’t leak). Then start tasting. If when you bite into one it still puckers your mouth, it’s not quite done. It should be very salty, and tart, but not overtly citrusy.

If you want to get fancy, add some peppers or spices to the jar.

Now, an obvious question is: Why is this safe to eat? And, Do I need to refrigerate this? And, what’s with the plastic lid? The third question is the easiest. The liquid is very acidic, and a regular metal canning lid will eventually rust. That doesn’t mean you can’t use one, but be aware that you probably won’t be able to reuse the lid. The second question is a definite maybe. Some people do, some don’t; I do, to stay on the safe side. The answer to the first is the crux of most food preservation. The combination of salt and high acidity (from the lemon juice) discourage the growth of bad bacteria, allowing the tastier kinds to flourish. If you don’t use enough salt, or enough lemon juice, or your kitchen is too hot, you might get mold. If, when you open the jar, it smells bad, or the the lemons appear slimy, throw it out and try again. And in fact, this is why you shouldn’t add water to the jar if it needs more liquid: the water will dilute both the percentage of acid (from the lemon juice) and the salt in the solution.

So remember: salt is your friend!