Welcome to the first installation of Baking Tips, an occasional series in which I whip up tips on how to become successful in the baker’s kitchen.
Summer is rapidly approaching for those above the belt. Do you know what that means? So is the canning season! Nothing beats making a substantial bulk of your favourite jam and sharing it with family and friends.
Depending on the acidity of the fruit, properly sealed jars can be stored at room temperature for up to a year. After filling the jars, wiping the rims with clean paper towels and applying the lids and rings, there are two techniques to create a strong, long-lasting seal.
Boiling water bath — Filled jars are placed on a rack and completely submerged in a large, deep stockpot of boiling water with the lid left on. Make sure the jars are at least 5 cm (2 in) below the water surface. Follow the recipe for the timing. This is the most effective sterilising and sealing technique. It is especially ideal for high acid product that could react to the metal lid.
Inversion — Filled jars are turned upside down on their lids. Simply let them cool. This technique works best with jolly hot product. Otherwise, it will cool down too much and not create a seal. If your product is high in acid, some discolouration is to be expected. It is recommended to preheat the jars, lids and rings to sterilise them before proceeding.
Steam canners may sound promising, but they are actually useless. Steam is not consistent in terms of temperature; it cools on contact with warm jars. Steam also doesn’t have the same heat penetrating power as boiling water bath.
If the seal fails, put the jam in the refrigerator. It will be there waiting for you to spread your toast with in the morning.