COLEMAN puts enormous effort into breeding a mustard plant that would be considered useless in its native countries because it yields little oil and is easier to make powder from ("Some still like it hot", Review, 23 July). But we don't need the powder - we have kitchen appliances that will reduce fresh seed to pulp. What we need is the oil. Michael Bateman says that it's bland, but it's a lot less bland than any cooking oils in the shops, unless you steep chillis in them for a month. And it's difficult to get.

Instead of mustard powder, why doesn't Unilever give us the powders made from tomato, mushroom and spinach that are used for making soups and red and green pastas, but which you can't buy?

Nick du Quesne Bird,

Bath, Avon