2 kg (4 lb) tomatoes
Roughly chop the tomatoes and process in a food processor. Line a sieve with muslin or a thin kitchen cloth and place over a plastic container. Pour in the pureed tomatoes, cover with plastic wrap (cling film) and let stand overnight. The next day, carefully lift off the sieve and discard the tomato pulp. The liquid that remains can be stored in the refrigerator for up to 4 days. It can also be frozen.