MAKES ABOUT 1 CUP
4 cups pure carrot juice
Pour the carrot juice into a resealable freezer bag and seal it. Put it in your freezer and squeeze the bag every hour or so to break up large ice crystals as they form. You want to end up with frozen juice that is the consistency of sno-cone ice or a granita. This may take up to 6 hours.
Once all of the liquid is frozen into ice crystals, pour it into a fine strainer or sieve set over a bowl. As it thaws, the concentrated carrot juice will thaw before the water does and flow out of the ice into the bowl. Let the frozen juice drip for 20 to 40 minutes, until most of the color has left the ice and you have a deep, rich concentrate in the bowl. You should have about 1 cup of concentrated juice. Discard the remaining ice crystals. Refrigerate until ready to use. (This juice will keep for up to a week in the refrigerator or 6 months in the freezer.)
CRYOCONCENTRATIONS
Sugar and salt solutions have a lower freezing point than water, which allows us to make superconcentrated juices through the process of cryoconcentration, a technique taught to us by the good people of CREA (Culinary Research & Education Academy). When you defrost the frozen mixture, the first part to melt is the pure juice, which you can capture (discard the remaining flavorless ice).
Pour the juice of any fruit or vegetable into a resealable freezer bag and seal it. In the restaurants, we love to do it with the juice of peak-season produce: peas, asparagus, apples, tomatoes. You can even do it with store-bought juices as your base. All you need to do is follow the instructions above for the Cryoconcentrated Carrot Juice. You can repeat this process as many times as you want, depending on how concentrated you want your liquid to be.
Use these superconcentrated juices in sauces, vinaigrettes, or cocktails. Admittedly, it’s a bit of work, but they’ll give your cooking an astonishing purity and intensity of flavor that’s worth the effort for the ambitious home cook.