How to Make Homemade Jam in Kilner® Preserve Jars

By Kilner® - Iconic Glass Jars, Bottles & Equipment | Kilner® | Published: 2026-10-27

Category: How-to Guides

Learn the simple steps to make small-batch homemade jam using Kilner® preserve jars, including sealing tips and common mistakes to avoid.

Quick Answer

You can make delicious homemade jam in a Kilner® preserve jar by following a simple stovetop method, then sealing it with the two-piece metal screw top for a proper vacuum.

Why Small Batches Work Best for Beginners

Starting with a small batch—like the 0.25 litre size—makes jam making less intimidating and reduces the risk of overcooking or under-setting. It also lets you experiment with flavors without committing to large quantities.

Smaller jars also cool and seal faster, which helps you confirm the vacuum seal worked before storing longer-term.

Choosing the Right Jar Size

The Kilner® 0.25 Litre Preserve Jar is ideal for individual portions or gifts. Its compact size means you can fill several jars from one batch, making it perfect for testing new recipes.

If you plan to store jam for months, ensure the jar is properly sterilized and the seal is intact—the metal screw band and replaceable vacuum seal work together to keep contents fresh.

Step-by-Step Jam Making in Kilner® Jars

Sterilize your jars: Wash the Kilner® 0.25 Litre jars and their metal screw bands in hot soapy water, then rinse. Place them in a preheated oven at 140°C (275°F) for 10 minutes, or use a dishwasher hot cycle. Keep them warm until filling. Never touch the inside of the sterilized jar or the vacuum seal with your fingers.
Prepare your fruit and sugar: Use about 500g of prepared fruit and 400g of sugar for a small batch. Toss the fruit with sugar and let it sit for 30 minutes to draw out juices, which helps the jam set evenly. Don't skip the resting time—it prevents sugar from crystallizing later.
Cook the jam to setting point: Heat the fruit and sugar over medium-high heat, stirring frequently until the sugar dissolves. Boil rapidly until the jam reaches 105°C (220°F) on a thermometer, or test by placing a small spoonful on a cold plate—if it wrinkles when pushed, it's ready. If you don't have a thermometer, the wrinkle test is reliable; just make sure the plate is cold.
Fill the jars while hot: Ladle the hot jam into the warm Kilner® jars, leaving about 1cm (0.4 inch) headspace. Wipe the rims with a clean, damp cloth to remove any residue that could prevent sealing. Fill one jar at a time and seal immediately to keep the temperature high.
Seal and cool to create a vacuum: Place the vacuum seal on the jar rim, then screw on the metal band until just finger-tight—don't overtighten. Turn the jar upside down for 2 minutes, then turn upright and let cool completely. As the jam cools, the lid should depress slightly, indicating a vacuum. If the lid pops up when pressed after cooling, the seal failed—refrigerate and use within a few weeks.
Label and store: Once sealed, label each jar with the date and flavor. Store in a cool, dark place for up to a year. After opening, refrigerate and consume within 4 weeks. Always check the seal before storing; if it's loose, treat as fresh and refrigerate.

Key Product: Kilner® 0.25 Litre Preserve Jar

Kilner® 0.25 Litre Preserve Jar: The Kilner® 0.25 Litre Preserve Jar features an easy-to-use metal screw top lid made of two pieces: a replaceable vacuum seal and a metal screw band to secure the seal. This two-piece design lets you check that the vacuum has formed by pressing the center of the lid after cooling, ensuring a proper seal for your homemade jam.
Kilner® 0.25 Litre Preserve Jar