Three pints of brandied blueberries processing in the canner now = me looking forward to winter
— Michele Grant (@opadit) July 6, 2014
The comment prompted a pal to ask:
@opadit Do those really need canning, or does the brandy preserve them?
— Brett Heller (@hellerbee) July 7, 2014
@hellerbee Need canning because not totally submerged in alcohol; liquid is mostly a very light syrup, only about 15% brandy.
— Michele Grant (@opadit) July 7, 2014
And then I realized that I really, really wanted to go on and give @hellerbee a better, more complete explanation by unpacking the questions he may or may not have known he was actually asking with his tweet. So here goes . . .
1. Doesn't alcohol preserve food? It sure does, and who doesn't like some rumtopf or tutti-frutti? You can safely preserve fruit in alcohol -- whether brandy, gin, rum, or vodka -- very easily at home. The main concern is that the spirit in which you submerge the fruit should be at least 40% alcohol, that is, 80 proof. (In her Encyclopedia of Country Living, Carla Emery states that a final product with 14% alcohol is "self-preserving" and gives a recipe for old-school tutti-frutti that relies on spontaneous fermentation, suggesting adding a package of yeast at the outset "to get the fermentation off to a quick start." I don't recommend relying on the natural yeast present in the skins of the fruit I bring home; and while I love the Encyclopedia and consult it regularly, I won't reproduce Emery's recipes here, because I'm a very conservative home canner.)
If you start with unblemished fruit, prepared in a clean kitchen, and steeped in strong, undiluted alcohol in clean jars or crocks, then your fruit preserved in alcohol, or the infusion or cordial you make with it, will stay safe for years, without heat any processing at all. Happy tippling!
This product, though, isn't preserved with the alcohol added to it. It's not so much a boozy fruit as it is essentially an ordinary hot pack method for canning berries. The brandy adds flavor without a whole lot of kick -- while it's still for grownups only, a serving of these berries will be nowhere near as devastating as a spoonful of rumtopf.
2. Doesn't sugar preserve food? Not really. I mean to say, hard candies can last indefinitely. What keeps hard candies from spoiling isn't the presence of sugar but the absence of microorganisms and water in a product that was brought to 320 degrees F (160 C) during its preparation. This temperature is well above the 240 degrees F needed to destroy C. botulinum. Home-canned foods, however, don't reach the same very high temperature as the sugars in a hard candy -- unless your jelly has gone terribly wrong.
I think there is a misconception that sugar acts like salt in preserving food, but that's not the case. Salt draws water out of a food item, depriving microorganisms of the moisture they need to survive and reproduce. When you see sugar included in recipes for pickling or curing (PDF), it's there for flavor, not for preservation (PDF). When you see it in a recipe for jelly, jam, fruit butter, or any other soft spread, it's there as part of the chemistry for the product's gel, as well as for flavoring the product and preserving the fruit's color. When you see it in a recipe for canning whole or chopped fruit, it's there to help the fruit "retain its flavor, color, and shape." Everyone says this but they don't explain why (PDF). I haven't had a chemistry class since 1988, but my guess is that the syrup, since it's saturated or super-saturated with dissolved sugar, will tend to approximate the same concentration of sugar as the fruit itself has, so it doesn't draw out the fruit's juices the way that plain water would.
3. So how did you do the brandied blueberries, then? As usual, if you are not familiar with home canning, please see the National Center for Home Food Preservation. This recipe does not substitute for a complete set of instructions on safe home canning practices.
Rinse the blueberries gently under cool water. Place them in a very large saucepan and cover with water. Add sugar. Heat thoroughly until sugar is dissolved and berries have darkened and swelled, stirring gently. Do not break or crush berries.
Pack hot pint jars with hot berries. Add 1 or 2 oz. brandy and 1 tsp. bottled lemon juice to each jar. Top off jars with syrup, leaving 1/2-inch headspace. Process pints 15 minutes in a boiling-water bath canner.
Store at least 6 weeks before using.
Lemon juice is added as an optional complementary flavor booster.
Refrigerate the leftover syrup and stray blueberries and use within 1 week. Suggestion: use as a base for a cool summertime soda by mixing with unflavored, unsweetened seltzer water to taste.