1 Clean sealable jars (for a total capacity of 600 ml) (approximately 2 1/2 cup total capacity) together with matching lids in a pot of boiling water and leave upside down to drain on a kitchen towel. Peel onions, halve and cut into wedges. Peel garlic and cut into thin slices.
2 Rinse thyme and rosemary, shake dry and pluck leaves or needles.
3 Combine vinegar, sugar, onions, garlic and herbs in a pot. Bring to a boil, cover and cook over medium heat for about 15 minutes.
4 Meanwhile, rinse grapes, drain and cut in half or into quarters, depending on size. Remove any seeds.
5 Add grapes to onion mixture, return to a boil and then cook over low heat until softened, about 15 minutes more.
6 Season chutney with salt and pepper and immediately pour into prepared jars, seal and let cool for 5 minutes upside down. Turn jars right side up and leave to cool completely. (Store chutney refrigerated for up to 2 months.)
Tip: To preserve the chutney for longer, you will need to process the jars according to manufacturer's instructions, or visit http://nchfp.uga.edu/.