It is written on most milk bottles, but is also used as a process for fruit juice: Pasteurised. But what exactly does that mean? We will explain here how the process works and what influence the brief heating has on the microorganisms and thus the juice. We will mainly explain pasteurisation in relation to juice, but other foodstuffs such as wine, beer and the already mentioned milk are also preserved with this process.
Pasteurisation as a process was invented by Louis Pasteur, who also gave the process its name. He recognised in the 19th century that heating for a short time kills most microorganisms and makes food last longer - without any significant change in the product's properties. Today, it is a legal requirement in Germany that certain foods must be pasteurised. This includes almost every type of milk, except raw milk, for example. Certain foods such as fruit juice are pasteurised because they would spoil too quickly due to the natural presence of microorganisms. The shelf life of food is therefore significantly extended by pasteurisation.
Whether a juice is pasteurised or not cannot be seen by simply looking at it. The gentle heating process does not cause any change in colour and the consistency does not change either. Pasteurising the juice only physically ensures that the fruit juice is more durable.
In our juice production at Rabenhorst, the pressed fruit juice, which is the basis for all our juices, is pasteurised particularly gently. We use a special pasteurisation process in which the juice is heated to temperatures of approx. 80-90°C. This process prevents the juice from fermenting. This process prevents the juice from fermenting. This is because the heating process kills the naturally contained microorganisms in the juice. These microorganisms, also called germs, would otherwise trigger the fermentation process and thus lead to the fruit juice spoiling.
Excursus: Why brown bottles?
Due to the gentle pasteurisation process, our Rabenhorst juices have a shelf-life of between 14 and 36 months, depending on the product. You should nevertheless store the bottle in the refrigerator after opening and consume it within a few days. Before opening, it is advisable to store the juice bottle in a rather dark place. Sunlight changes the taste of the juice and vitamins can be lost. For this reason, we only fill our high-quality fruit juice into brown bottles, as amber glass offers good protection against both UV light and short-wave visible light. This way, the vitamins and ingredients are optimally protected.
Since the addition of preservatives is prohibited by law, pasteurisation is used to preserve fruit juice. This is how you can do without the use of preservatives. Due to our very gentle pasteurisation process, vitamins and other heat-sensitive ingredients are largely preserved in the juice. The colour, taste and smell of the fruit also remain unchanged. Our juices therefore taste particularly fruity, for example our pure juice from first pressing, which you can drink pure or diluted, depending on your preference.
What does gently pasteurised mean?
To pasteurise food gently means to heat it only as long as necessary. Because the longer a food is heated, the greater the risk that the vitamins it contains will also be destroyed. That's why we at Rabenhorst pasteurise our juice particularly gently for a short time at 80-90° Celsius.
What is the difference between pasteurisation and sterilisation?
Pasteurising food means heating it to a temperature below 100° Celsius for a short time. This kills many germs and stops enzymes. However, heat-sensitive microorganisms remain. That is why juice, for example, does not keep indefinitely even if it has been pasteurised. Sterilisation, on the other hand, means that the food is heated to about 130° Celsius for up to one hour. After that, they are completely germ-free and can be kept for several years. However, vitamins are also destroyed in the process.
Which foods are pasteurised?
The best known is the pasteurisation of milk. The milk is heated to 72-75°C for 15-40 seconds and then immediately cooled down again. About 99.5 per cent of all germs in the milk are killed. Pasteurised milk can be kept in the refrigerator for up to 6 days. Pasteurisation is a legal requirement for all types of milk in Germany, except for raw milk and milk from speciality dairies. However, pasteurisation is also used for other foods such as wine, fruit juice or beer.