Preventing Discoloration

Vegetables that discolor easily, such as celery root, salsify and artichoke bottoms, may be cooked in a blanc (below) or with acid to keep them white. They should also be cut with a stainless steel knife to prevent discoloration from carbon steel, and the pieces should be dropped into acidulated water until all the vegetables are prepared and ready for cooking.

1. To make a blanc: bring a pan of salted water to a boil. Make a soft paste by stirring water into flour, allowing 3 tbsp/45 ml water and 1 tbsp flour for every 1 qt/1 L of water. Stir this into the boiling water and add the juice of half a lemon for every 1 qt/1 L. Add the vegetables and boil for the usual time.

2. Acidulated water: add the juice of two lemons to 1 qt/1 L cold water. Immerse the vegetables until ready to cook them.