It has for several years been a source of mild frustration to me that I cannot find a reliable recipe for preserves. I have all kinds of recipes for chutneys and conserves and marmalades, and for jams with honey and low-sugar jellies and for special preserves made from this or that sort of (where I live) unattainable stone fruit. What I want is simply strawberry preserves, peach preserves, blackberry preserves, and there, so far as I can tell, are no well-tested recipes to be had in books.

For basic jams and jellies, of course, the folded sheet in the box of pectin gives me instructions, but the point of preserves is not to use boxed pectin. Preserves is fruit with just enough sugar to literally preserve it, and perhaps a touch of fresh lemon juice if even that much sugar seems too sweet; it is stirred and tended while it cooks down; it is soft on the spoon and in the mouth, not molded like a school-lunch dessert. To make true preserves is to capture the essence of fresh summer fruit and hoard it away in a cupboard for the horrible soggy February morning when you simply cannot face another day of winter, and you open it up and spoon dollops onto buttered toast and feel that perhaps you can live another day.

I’ve made jams every spring and summer for — well, for a lot of springs and summers. Jam is crushed fruit, sugar, and (unless the fruit is naturally high in pectin) powdered pectin, and homemade jam packs far more flavor than store-bought. But in the past few seasons I’ve been working toward that Platonic ideal of preserves, and I’ve had to work largely by feel.

Powdered pectin helps you in a few ways if you’re making jam. It adds reliabllity, first of all. Pectin is the substance that, with sufficient sugar, acid, and heat, causes jelly to jell. Many kinds of fruit naturally contain enough pectin to jell, but some, like blackberries, lose their pectin as they ripen. The rind of oranges and lemons contains pectin, as do Concord grapes and apples, which is why grape jelly, apple jelly, and marmalade are all fairly easy to make. But with most fruit, only experience can tell you how much pectin you’re working with, and some fruit (like strawberries or peaches) contains no pectin at all. In these cases, you have to cook the jam down slowly, with care and attention, and to know by sight and by feel when it’s ready. Powdered pectin is also fast. The recipe I always used for strawberry jam calls for boiling exactly one minute; my strawberry preserves cooks down for half an hour.

But all that extra pectin also requires more sugar to jell. That stretches the fruit further — which means extra profit if you’re a large manufacturer, but if you’re processing the strawberries you picked this morning, all that sugar waters down the flavor of the berries. Blackberries, I’ve found, can stand up to a full-bore sucrose assault, but strawberries and peaches have delicate flavors that are quickly buried in pure sweetness.

When I started looking for recipes for preserves, I found dozens on the internet. But they vary wildly. Recipes for blackberry preserves, for example, call for ratios of berries to sugar ranging from one-to-one to nearly three-to-one. Who to believe?

My working theory has been that decades of eating commercial jams, jellies, and so-called “preserves” — not to mention Ho-Hos and Fruit Loops — have ruined people’s tastes so that they expect a highly sweetened product. In the “old days,” I reasoned, sugar was more expensive, and people weren’t used to eating so much of it. Traditional preserves would have used just barely enough sugar to tie up the available water in the fruit and prevent decay. But how much was barely enough?

Last year I made strawberry preserves with ratios of 8 cups fruit to 3½ cups sugar, and it tasted — well, it tasted like strawberries. To say that something out of a jar tastes like strawberries sounds incredible if you have recently eaten a fresh-picked, just-ripe strawberry; I don’t say it lightly. And in the proverbial cool, dark place, it kept just fine until the following spring. So I’m guessing that proportion is “barely enough sugar” to preserve the strawberries. Last week I made peach preserves with just about the same proportions — a bit less sugar than I’ve used in the past; we’ll see how it holds up. I have better canning technology than they did in the “old days,” so I think it will be just fine, though an open jar in the fridge may not last indefinitely. But the flavor is so good that I can’t see an open jar lasting indefinitely in any case.

All this research and calculation has been necessary to re-create something that was once passed down by example and learned by feel, and which is so utterly simple as barely to need a recipe. Making preserves requires nothing fancy but a good deal of care and thoughtful work and knowledge that can be gained only by experience — stirring as the fruit simmers down, watching as the mixture turns glossy and jewel-toned, observing the way it falls from a spoon (not quite in sheets, as the books will tell you), trusting enough in the ultimate variability of things to put a dollop in the freezer for half a minute to see what it will really look like when it’s cooled. Somehow it seems that the simplest things always take the most care.