A cook has many options for intensifying the flavor of liquids that come from food. The alternatives range from the traditional boiling pot on the stove to the more exotic and expensive, such as Genevac's Rocket Evaporator, which is part centrifuge and part distillery. You can use any of these strategies to concentrate a juice, jus, or broth.

Strategy

Description

Pros

Cons

stove-top reduction

boils off water to increase concentration of those flavor compounds that remain

inexpensive, easy

slow, many desirable volatile aromatics evaporate away or are altered by heat

vacuum reduction

lowers pressure of air above liquid, increasing rate of evaporation

inexpensive, straightforward to set up

volatile compounds still escape

rotary evaporation (rotavap)

distills and captures volatile components selectively at a controlled temperature and pressure

captures evaporated volatile aromatics, reduces without heat, processes large batches

expensive, complicated

vacuum concentration (with vacuum concentrator)

spins liquids at low speed, distills under vacuum, and condenses evaporated components

simple automated process, handles up to six liquids at once, precise temperature control, low-speed centrifugation

expensive, complicated

forms crystals of pure ice that force particles and dissolved substances to concentrate in remaining liquid

very inexpensive and simple, requires no special equipment, no volatiles escape or change

slow, limited degree of concentration

reverse osmosis

forces liquid through a semi-permeable membrane through which water but not flavor compounds can pass

energy-efficient, commonly used in water purification and winemaking

complicated, not yet adapted for culinary use