Rehydrate

To rehydrate a dried food is to restore some of its moisture by soaking it in water or another suitable liquid. Rehydration softens the food and makes it easier to cook or use in a recipe. The time required depends on the food’s size, density, drying method, temperature and the liquid used.

Foods commonly rehydrated

• Dried mushrooms: soak porcini, shiitake or other dried mushrooms until softened. Strain the soaking liquid carefully through a fine filter to remove grit before using it in stocks, sauces or risotto.
• Dried fruit: plump raisins, apricots or prunes in water, tea, juice or another recipe-suitable liquid.
• Dried chillies: soak in hot water to soften before blending into pastes and sauces; remove stems and seeds as required.
• Dried beans and legumes: soak selected varieties to shorten cooking time and promote more even hydration. Not all legumes require soaking.
• Gelatine: hydrate powdered or sheet gelatine according to the manufacturer’s instructions before dissolving it into a warm preparation.

How to rehydrate foods

Choose a liquid that complements the intended dish. Use enough liquid to cover the food, allow room for it to expand, and give it sufficient time to soften. Warm liquid often speeds rehydration, but very hot water can affect delicate ingredients or extract unwanted flavours. Drain or squeeze only when the recipe calls for it; some foods should retain moisture.

Food safety and storage

Rehydration does not sterilize food. Follow safe handling instructions for the product, and do not leave rehydrating ingredients at room temperature for extended periods. Refrigerate foods when soaking times require it, particularly when the ingredient is potentially hazardous or the process is prolonged. Use rehydrated foods promptly or store them under appropriate refrigerated conditions.

Rehydration versus infusion

Rehydration restores water to a dried ingredient. Infusion extracts flavour or aroma from an ingredient into a liquid. The two can happen at the same time—for example, dried mushrooms soften while releasing flavour into their soaking water—but they describe different objectives.

Chef’s tip: taste the soaking liquid before using it. It may add valuable flavour, but it can also contain sediment, excess bitterness or an intensity that needs adjusting.