Adapted Fish Sauce

• 1 l. carton white grape juice
• 1 bottle ‘Oyster brand’ fish sauce or a pale variety of fish sauce<

Tip the grape juice into a large saucepan and bring to a gentle simmer. Cook at the lowest setting for however long it takes to reduce by half. This is never set in stone as grape juice can have a higher or lower sugar content. Cool and store. You can use this for other recipes in Apicius as well as for your fish sauce. The ratio that works for me is two-thirds fish sauce to one-third gr