Thor, the pre-concentrator for tomato juice production

The THOR pre-concentrator from Ing. A. Rossi is the most technologically advanced and energy efficient solution on the market for the production of high quality tomato juice.

THOR is designed with an integrated Hybrid Flow heat exchanger system at each evaporation phase and is designed for intermediate viscosity products.

This unique solution by Ing. A. Rossi allows you to reach a very precise and considerably higher Bx level than any pre-concentrator on the market; with THOR you have the opportunity to obtain finished products such as tomato puree and pizza sauce, preserving liquid for pulped, peeled or diced tomatoes fillings and intermediate viscosity juices with the additional advantage of obtaining different products at the same time in the same evaporator.

THOR's Hybrid Flow heat exchange, which maximises MVR mechanics, makes it the most energy-efficient evaporator on the market.

What are the advantages of THOR

  • Quality: its technology delivers improvements in product quality, colour and organoleptic properties due to the low evaporation temperature together with the reduced residence time.

  • Steam saving: the balance point is reached about 30 minutes after starting the machine and the MVR technology means that no more steam is consumed with Hot Break products.

  • Modularization: THOR is designed to be modular, so columns and their respective booster pumps can be added post-installation, depending on the required capacity or planned investment.

  • Flexibility: the unique Hybrid Flow (mixed) technology allows production capacity to be adapted or diversified  for each evaporation column, according to needs. This can run at maximum capacity or can be reduced by up to one fifth of the total.

  • End-of-cycle washing: The high product velocity inside the heat exchanger guarantees very long cycles between washes compared to single-pass falling film technology. In this configuration, the interval between one washing cycle and the next can be between 40 and 70 days and so can cover an entire tomato harvesting period.

  • A single machine for different products: THOR's modular solution makes it possible to obtain products with different Bx in each evaporation column and even to process separate juices. For example, it is possible to extract an 8 Bx Cold Break juice to feed a three effect evaporator, while obtaining a 12 Bx Hot Break product, such as tomato puree, from a different column, ready for filling.

  • Energy saving: the energy balance of the machine has a steam equivalence ratio of 20 effects (1 kg of steam consumed per 20 kg of evaporation).


Industrial concentrators for tomato juice are machines used to concentrate fresh tomato juice efficiently. They are an important part of the production of tomato concentrate, which is used as a base for many food recipes around the world.

The process of tomato juice concentration starts with the washing and preparation of fresh tomatoes. The tomatoes are chopped and passed through a sieve to remove skins and seeds. The resulting juice is then heated to high temperatures to remove water and concentrate the active components of the tomato, such as flavours and nutrients. Most concentrators use a steam evaporation process to concentrate the juice.


"MVR" stands for "Mechanical Vapour Recompression" and refers to the use of a mechanical compressor to recover the process vapour generated during evaporation, to increase its pressure and temperature and to reuse it during the evaporation process.

The MVR hybrid concentrator combines the energy efficiency of falling film concentrators with the flexibility of vapour recirculation concentrators, which use a heat exchange system to concentrate the liquid.

The MVR hybrid concentrators from Ing. A. Rossi are designed to guarantee an exact and constant Brix, ensuring high quality both for products such as tomato puree and pizza sauce and for the production of tomato concentrate, while maintaining the high organoleptic properties of the inflowing fresh tomato juice.


The concentration of tomato juice can be measured using several methods, including refraction, density and the determination of solubility. The choice of method depends on the specific requirements of tomato concentrate production.

The most commonly used of these methods is refraction, which is based on the liquid's ability to refract light. Using a refractometer, the angle of refraction of light passing through the liquid is measured.

The concentration of tomato juice can also be determined by its density, measuring it with a hydrometer which directly measures the specific gravity of the liquid. Often, this method is used for the production of tomato concentrate, as the density increases with the concentration of the juice.

Finally, the solubility of tomato concentrate can also be used to measure its concentration. This method is based on the ability of the concentrate to dissolve in a predetermined volume of water.


Brix is the unit used in the food industry and agriculture to measure the concentration of sucrose in a liquid, such as checking the amount of sugar in fruit, vegetables and beverages, including tomato juice.

Brix is often used as an indicator of the ripeness and quality of the food product, as the sugar concentration increases as fruit and vegetables mature. It is also used to determine the extraction rate of tomato concentrate during concentration, with a higher Brix indicating a higher concentration of tomato juice.


Maintaining a temperature that is not too high during tomato juice concentration is important to maintain the high quality of the final product.

Excessively high temperatures can cause various effects in the concentrate and so in the final product:

  • Denaturation of the proteins and a reduction in the aromatic content of the juice would lead to a less pleasant final taste and aroma.
  • A reduction in the stability of the concentrate would favour the formation of undesirable compounds and the oxidation of nutrients.
  • An increased risk of bacterial contamination and the proliferation of unwanted microorganisms would result in a lower macrobiotic quality and an increased risk of food contamination.


Hot Break and Cold Break are two common methods used for the production of tomato concentrate.

Hot Break is the process in which tomato juice is exposed to a temperature of up to 98°C for a period of time. This process helps to denature the proteins and release the enzymes in the tomato juice, making the concentrate denser and less viscous.

The result of Cold Break (in which enzymatic deactivation is carried out at lower temperatures) is a tomato concentrate that is more viscous than that produced by the Hot Break process.


The forced circulation evaporator is indispensable in the concentration of very viscous liquids with high levels of final residue, such as tomato concentrate, hot break" and "cold break, or very thickened concentrated fruit and vegetable purees.

Ing. A. Rossi offers a wide range of continuous systems, both in terms of capacity and energy efficiency, according to single, double and triple-effect versions.

In these evaporators, the liquid to be concentrated is circulated via a pump in a heat exchanger which is heated by steam.


The reuse of steam generated in an evaporator in a second unit operating at a lower temperature is the principle behind multiple effect evaporation, which is used to save steam. 

In simple evaporation, the live steam that is condensed in the heating section of the evaporator transfers its latent heat to the solution by vaporising part of it. Using multiple effect evaporation, the latent heat of the live steam is transferred to the steam generated by the solution. If this heat were lost, the system would only make partial use of the steam.

The steam can be used again by sending it to the heating section of a second evaporation effect, provided the temperature in the latter is reduced. This is done by lowering the pressure to a level where condensation is possible.

The highest temperature phase is carried out in the effect where the degree of concentration is lowest, while the finishing effect, where the highly concentrated product can easily undergo organoleptic changes, operates at a much lower temperature.


The THOR pre-concentrator from Ing. A. Rossi is the most technologically advanced and energy efficient solution on the market for the processing of products such as tomato puree, pizza sauce, rustic puree, filling liquid (or preserving liquid) for pulped, peeled or diced tomatoes and other intermediate viscosity tomato juices. THOR is also used for the pre-concentration of Hot Break and Cold Break tomato juice for concentrate production.

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