Homemade Grape Jam Is Nearly Effortless With This Slow Cooker Technique - Tasting Table

"Grapes ripen in a short window of time, and they're fragile, so they don't wait patiently. Preserving a fleeting harvest is what jam was invented for, but grape jam can easily get messed up on the stovetop. Grapes are naturally very high in sugar and relatively thin-skinned, which means traditional jam-making requires a watchful eye. As the hot mixture reduces and the water cooks off, the sugars concentrate and the jam gets progressively jammier and denser."

"But jam doesn't actually need high heat to set; it mainly needs steady evaporation to concentrate the sugars, and to get to 220 degrees Fahrenheit to activate the pectin. A slow cooker, by design, keeps temperatures low and consistent, way below the point where the grape jam's sugars could caramelize or burn. Over several hours, the excess water from the fruit will evaporate gently and the jam will thicken perfectly, without constant stirring or babysitting."

"To make grape jam in a slow cooker, add your de-stemmed, washed grapes directly to the crock, and crush them slightly to release their juices; you can use your hands (fun!) or a good potato masher for this part. Then just turn the cooker to low and let time do the work. As the fruit softens, the skins will break down and the mixture will slowly thicken."

Grapes ripen quickly and are fragile, creating a short harvest window that jam can preserve. Stove-top jam risks scorching because high natural sugars concentrate as water evaporates and pot bottoms can overheat before proper thickening. Jam primarily needs steady evaporation and reaching 220°F to activate pectin, not high heat. Slow cookers maintain low, consistent temperatures that prevent caramelization and allow gentle evaporation over hours, producing thick jam without constant stirring. For slow-cooker jam, destem, wash, slightly crush grapes, cook on low until skins break down. Because grapes contain natural sugars and pectin, added sugar is optional though it aids preservation for canning.

Read at Tasting Table