Juice concentrate is made by extracting juice from fresh fruit and then removing most of the water, leaving behind a thick, flavor-dense syrup. The most common method uses heat-based evaporation, but freeze concentration and membrane filtration offer alternatives that better preserve nutrients and flavor. Once the water is removed, the concentrate can be shipped at a fraction of its original volume and later reconstituted by adding water back in.
From Whole Fruit to Fresh Juice
The process starts the same way regardless of the concentration method. Fruit is washed, sorted, and mechanically pressed or squeezed to extract raw juice. For citrus fruits, specialized machines peel and ream the fruit. For apples or grapes, the fruit is crushed and pressed through filters. The extracted juice is then screened to remove pulp, seeds, and other solids before moving to the concentration stage.
Thermal Evaporation: The Standard Method
Most juice concentrate in grocery stores is made through thermal evaporation, which works by gently boiling off water under reduced pressure. Lowering the pressure inside the evaporator drops the boiling point of water well below 100°C, which helps limit heat damage to the juice. Typical processing temperatures sit around 65°C, significantly lower than a full boil.
Industrial facilities use multi-stage evaporators to make this process efficient. The steam produced in the first stage feeds the heating system of the second stage, and so on, creating a chain of two to six stages. Each stage removes more water while recovering heat from the previous one. By the end, the juice has been reduced to a thick syrup, typically reaching a sugar concentration (measured in degrees Brix) that meets regulatory standards. For reference, the FDA considers single-strength apple juice to be 11.5 Brix and orange juice 11.8 Brix. Concentrate is several times more dense than that.
The obvious problem with heating juice is that it drives off the volatile compounds responsible for fresh flavor and aroma. To counter this, most modern facilities use an essence recovery system. As the juice heats up in the first evaporation stage, the aromatic compounds that evaporate are captured separately, condensed, and stored. These flavor essences are then added back into the finished concentrate, restoring much of the original taste profile.
Freeze Concentration: A Cold Alternative
Freeze concentration takes the opposite approach. Instead of boiling water off, it freezes some of the water in the juice into pure ice crystals. Those crystals are then physically separated from the remaining liquid, usually by centrifugation or filtration. What’s left behind is a more concentrated juice.
This method avoids heat entirely, which means fewer flavor compounds are lost and more heat-sensitive nutrients survive the process. Studies on freeze-dried and freeze-processed fruits consistently show better vitamin C retention compared to thermal methods. In one comparison, thermal processing of tomatoes (which involved heating at 92°C, concentrating at 65°C, and pasteurizing at 100°C) destroyed roughly 80% of the vitamin C. Freeze-based methods preserved significantly more.
The tradeoff is cost. Freeze concentration requires more energy and specialized equipment, so it’s mainly used for premium juice products or fruits where delicate flavor compounds justify the expense, such as apple juice.
Membrane Concentration
A third approach skips both heat and freezing. Membrane concentration uses physical barriers with microscopic pores to separate water molecules from the juice. The juice is pushed against these membranes under pressure, and water passes through while the larger sugar, flavor, and nutrient molecules stay behind.
Several variations exist. Reverse osmosis uses high pressure to force water through a tight membrane. Osmotic distillation and membrane distillation use differences in vapor pressure or temperature across the membrane to draw water out more gently. All of these qualify as non-thermal methods, meaning they preserve flavor and nutrients better than evaporation. However, they’re slower and generally can’t achieve the same extreme levels of concentration as thermal evaporation, so they’re sometimes used as a first step before a final evaporation stage finishes the job.
What Happens to the Nutrients
Concentration preserves most of the sugars, minerals, and fiber found in fresh juice. The main nutritional casualty is vitamin C, which breaks down rapidly when exposed to heat. The degree of loss depends heavily on the method. Thermal evaporation at standard industrial temperatures can destroy a large percentage of vitamin C, with losses reaching 80% in some cases. Freeze concentration and membrane methods perform much better on this front.
Other nutrients are more resilient. Potassium, calcium, and most B vitamins survive concentration reasonably well. Antioxidant compounds like the polyphenols in grape or pomegranate juice also tend to concentrate along with the sugars, meaning the finished product can actually have higher antioxidant levels per volume than the original juice. The catch is that some of these compounds degrade during the long storage periods that concentrate enables, so the nutritional profile when you finally drink it depends on how long it sat in a warehouse.
Why Concentrate Exists: Shipping and Shelf Life
The primary reason juice is concentrated has less to do with flavor and more to do with logistics. Removing most of the water from juice dramatically reduces its weight and volume, making it far cheaper to ship from growing regions (like Brazil for oranges or China for apples) to bottling plants worldwide. A tanker of concentrate represents several times more finished juice than the same tanker filled with regular juice.
Concentration also extends shelf life. The high sugar density of concentrate creates an environment where bacteria and mold struggle to grow. Stored properly, frozen concentrate can last well over a year. By comparison, “not from concentrate” juice (which is pasteurized but never has its water removed) requires refrigeration or aseptic packaging and generally has a shorter shelf life, though aseptic storage in oxygen-free tanks can preserve it for close to a year as well.
From Concentrate Back to Juice
When concentrate reaches a bottling facility, it’s reconstituted by mixing it with filtered water until it returns to the Brix level of single-strength juice. The restored flavor essences captured during evaporation are blended in, and the juice is pasteurized one final time before packaging. This is why your carton says “made from concentrate” rather than just “concentrate.”
Some products are sold as frozen concentrate for home use, where you add the water yourself. The ratio printed on the can (typically three parts water to one part concentrate) is calibrated to hit that same target sugar concentration. Whether reconstituted at a factory or in your kitchen, the goal is the same: a product that tastes and measures as close to single-strength juice as possible.