Concentrate is made by removing most of the water from a liquid, usually juice, to reduce its volume and weight. The core process is simple: extract juice from fruit or vegetables, then pull out water using heat, pressure, freezing, or membranes until the liquid is several times more dense than it started. What varies is the method, and each one affects the flavor, color, and nutritional value of the final product differently.
The Basic Process: From Fruit to Thick Syrup
Every concentrate starts with raw juice. Fruit or vegetables are washed, crushed, and pressed to extract their liquid. That fresh juice is mostly water, typically 85 to 95 percent depending on the source. The goal of concentration is to strip away enough of that water to leave behind a thick, shelf-stable product that’s cheaper to store and ship. The sugar content of juice is measured in degrees Brix, where fresh orange juice sits around 11 to 12 Brix and a finished concentrate might reach 42 to 65 Brix or higher.
Once the water is removed, the concentrate is cooled, packaged, and either frozen or stored at low temperatures. When it reaches the consumer or a bottling facility, water is added back in to reconstitute it to its original strength. That’s what “from concentrate” means on a juice label.
Thermal Evaporation
The most common industrial method uses heat to boil off water. In its simplest form, juice is heated in an open pan at atmospheric pressure until enough water evaporates. This works, but the high temperatures involved (around 89°C) and long processing times (over 75 minutes for some batches) cause significant damage. Color degrades noticeably, protective plant compounds break down, and flavor compounds literally evaporate along with the water.
To solve this, most modern facilities use vacuum evaporators. Lowering the air pressure inside the evaporator also lowers the boiling point of water, so juice can be concentrated at much gentler temperatures. A typical vacuum evaporator operates at around 45°C, roughly half the temperature of the open-pan method. This preserves more color, retains more of the plant’s natural antioxidants, and results in a better-tasting product. Multi-stage evaporators pass juice through several chambers at progressively lower pressures, making the process faster and more energy-efficient.
The tradeoff with any heat-based method is nutrient loss. Vitamin C is particularly vulnerable. Losses range from 20 to 90 percent depending on how hot the juice gets, how long it’s heated, and how much oxygen it contacts during processing. One study on tomato concentrate found vitamin C losses of about 80 percent after the full sequence of heating, concentrating under vacuum, and pasteurizing.
Freeze Concentration
Instead of heating juice to remove water as steam, freeze concentration chills it until ice crystals form. Since sugar, acids, and flavor compounds don’t freeze at the same temperature as water, the ice that forms is nearly pure water. Those crystals are then physically separated from the remaining liquid, which is now more concentrated.
The key advantage is that no heat ever touches the juice. This preserves virtually all of the original flavor, color, and nutritional content. The challenge is growing ice crystals large enough to separate cleanly from the thick liquid. Smaller crystals trap more juice and reduce efficiency. Processors control crystal size by carefully managing temperature and timing so that large, easily filtered crystals develop.
Freeze concentration is more expensive than thermal methods and slower to scale, which is why it’s typically reserved for premium products where flavor fidelity matters most.
Membrane Filtration
A third approach pushes juice through specialized membranes that allow water molecules to pass through while blocking sugars, flavors, and other larger molecules. Reverse osmosis is the most widely used membrane technique for juice concentration. It operates at room temperature, uses relatively little energy, and retains aroma and flavor compounds far better than thermal evaporation.
Membrane processes have practical limits, though. As the juice gets thicker, it creates higher osmotic pressure on the membrane surface, meaning the system needs increasingly powerful pumps to keep water moving through. For most polymer membranes, performance drops sharply above about 30 Brix. A 42-Brix orange juice concentrate, for example, would exert pressures above 90 bar on the membrane, which is costly and hard on the equipment. For this reason, many producers use membranes for the initial concentration stage and finish with thermal evaporation to reach the final density.
How Lost Flavors Get Added Back
When juice is heated during evaporation, volatile aroma compounds escape with the steam. These are the molecules responsible for the fresh smell and taste of fruit, and losing them is one reason reconstituted concentrate often tastes flatter than fresh juice. Producers don’t just accept that loss. The steam that comes off the evaporator carries those aroma compounds, and they can be captured.
Traditional recovery uses high-temperature distillation to separate aromatics from the condensed steam, but the heat can damage delicate citrus oils and other fragile flavor molecules. Newer approaches use membrane-based recovery, running the condensate through reverse osmosis or pervaporation systems that operate at gentle temperatures without chemical additives. These membrane systems can effectively double the operating capacity of a production line while improving both color and flavor compared to thermal evaporation or freeze concentration alone. The recovered essence is then blended back into the concentrate or added during reconstitution.
Botanical and Herbal Concentrates
The same basic logic applies to plant extracts used in supplements, herbal medicines, and food flavoring, but the starting materials and solvents differ. Instead of pressing juice from fruit, processors soak plant material in a solvent that dissolves the target compounds. Ethanol and methanol are the most common solvents for general phytochemical extraction. The solvent-loaded liquid is then evaporated, often under vacuum, to remove the solvent and leave behind a dense extract.
For heat-sensitive plant compounds, supercritical carbon dioxide extraction offers a gentler alternative. CO₂ is pressurized until it enters a state between liquid and gas, where it becomes an excellent solvent. It works at just 31°C, is non-toxic, and evaporates completely from the final product without leaving residue. Molecular distillation takes a different approach, separating compounds under deep vacuum at temperatures far below their normal boiling points. Both methods are especially useful for concentrating essential oils and other fragile botanical ingredients.
Why Concentrate Exists: Shipping and Storage
The economics of concentrate come down to physics. Water is heavy, and most beverages are 90 to 95 percent water. Removing that water before shipping and adding it back at the destination saves enormous amounts of fuel and packaging. One beer concentrate company reports its product travels at one-sixth the weight and volume of filled bottles or kegs, making it roughly eight times more efficient to transport. Another system claims five times the transport efficiency of conventional liquid shipping.
These reductions translate directly into lower carbon emissions from packaging, refrigeration, and freight. For a global juice industry moving millions of tons of product across oceans, the savings are substantial. Frozen concentrate also lasts far longer than fresh juice, allowing producers to process fruit at peak harvest and distribute it year-round without spoilage.
What “From Concentrate” Actually Means
The FDA defines juice concentrate as juice that has been “reduced in weight and volume through the removal of water.” Any product that could be labeled as 100 percent juice, or a concentrate of that juice intended for beverage use, must follow federal safety protocols during production. When you see “from concentrate” on a carton, it means the juice was concentrated at or near the source, shipped in bulk, and then reconstituted with water (and often the recovered flavor essences) at a bottling plant closer to you. “Not from concentrate” juice skipped the concentration step entirely and was pasteurized and packaged as a single-strength liquid. Both can legally be called 100 percent juice, and both are pasteurized. The difference is in the processing path, not necessarily the final nutritional content, though fresh-squeezed juice that was never heated will retain more vitamin C and a brighter flavor profile than a reconstituted concentrate.