The complexity of semi-hard cheese production
- and how to secure efficient operations
With renowned cheese types such as like Edam, Maasdam and Gouda, semi-hard cheese is one of world’s most popular varieties. However, from the producer’s perspective, semi-hard cheese has its challenges. Portfolio Manager Jurjen Van Den Berg and cheese technologist Roger Kroon give us a full rundown of how to stay on top of a complex production process.
The importance of milk quality
“If you have good fresh milk that is treated in the right way, you can make good cheese. So the most important thing is that the milk has a low content of microorganisms. This is obviously something every producer knows,” says Jurjen.
That you want to avoid contamination is not hard to understand. But is there more to the concept of “good milk” than meets the eye? Yes. Bacteria and milk freshness aside, the presence of antibiotic residues can pose a problem. Another issue is fat/protein ratio. And concentrations of lactose and calcium can vary. Even the ratio of the casein and whey protein can require the attention of the cheesemaker. These multiple fluctuations in milk compensation conflict with having a consistent, uniform output of cheese. To overcome this, constant monitoring of cheese milk composition, a good standardization process, and frequent checks of quality control points are needed to produce repeatable high-quality cheese.
“Standardized milk with exactly the composition you need – the exact amount of fats and proteins – lets you trim your cheese factory for optimal efficiency and stable output,” adds Roger. “Don’t forget the importance of calcium in the cheese milk. To ensure a uniform cheese structure and quality, the calcium concentration should be kept stable to create a repeatable coagulation strength. The Tetra Pak Coagulation sensor can help cheesemakers maintain a stable coagulation strength.
Production line design – where the details make the difference
“There are many parameters here that you need to get just right. For example, if your flow rates in the milk supply pipes are too high, you can get foam on your milk. And if you start making cheese with that, it affects the quality negatively. High velocity in the pipelines also creates curd fines, and you don’t want that.”
Further down the road (downstream) the process piping for the transfer of curd/whey mixture needs attention too. If the flow rates are too high (max 1.5 m/s), it will result in curd damage and fine losses. Furthermore, curd/whey lines should be designed with a minimum of obstacles. Pipe bends should, for example, be minimized and designed with a large radius.
The design of the milk pasteurizer can have an impact on the efficiency of a line. If the milk pasteurizer is designed correctly, has accurate control of pasteurization temperature, and can handle capacity fluctuations correctly, the formation of denatured whey proteins will be minimized. Denatured whey proteins reduce the quality and value of the total whey fraction.
That perfect moisture
Every cheese type has its own characteristics. Fat, moisture content and the type of starter culture make it special. In many cases these characteristics are legally restricted. A cheese with a moisture level that is too high will have an acid taste after ripening. In many cases it will also have a very sensitive and soft structure. Furthermore, too high moisture content can affect the cheese quality (irregularities). This cheese quality sets a limit to the maximum amount of moisture in cheese. A large variation in moisture content will force producers to lower the average moisture content to make sure claims or downgrading of the cheese is prevented. This is the fundament for the business case for the standard deviation of moisture in cheese. A perfect moisture balance gives semi-hard cheeses their firm, slightly elastic texture.
“You cannot exceed the max level of moisture content in a certain cheese type. If you go above that level, negative effects on taste and structure will appear. On the other hand, you want to sell cheese with a moisture level that is close to max because that reduces raw material costs – water is cheap!”
In other words: it is a matter of finding the sweet spot.
“You need good control, and a uniform composition of your cheese. The closer you can get to your ideal water content, the higher the yield.”
So how is the perfect moisture content achieved?
The base of cheese moisture accuracy starts with a good line setup. A reliable and stable moisture accuracy can be achieved when cheese lines operate according to a predefined, repeatable, fixed time schedule, batch after batch. That’s why it is important that equipment (unit operations) in a cheese line communicate with each other to maintain the time rhythm. If time deviations occur, it has a negative impact on moisture accuracy. To limit negative effects when disturbances occur, Tetra Pak has developed a dedicated “Time Rhythm control” module. This module actively controls time rhythm and anticipates or compensates when there are deviations.
Weight accuracy
An important KPI for a modern cheese factory is the accuracy of the cheese weights leaving the production line. For instance, in case cheese is cut into slices, it is crucial that the cheese have a uniform weight. A uniform weight ensures an efficient slicing process - every slice the same size(!) and weight – and limits downgrading of cheese.
If cheese is sold on E weight (fixed weight), it may not be sold underneath a certain minimum weight. In case the weight accuracy is very stable the cheese line can be trimmed to a target weight figure which is close to the minimum weight level. This limits the production costs.
Tetra Pak has extensive knowledge, with specialists available that can fine-tune Tetra Pak cheese lines for optimal performance. Furthermore, the Tetra Pak cheese lines are equipped with features and tools that will contribute to optimization of your lines, and make sure the accuracies are maintained during the year.
The need to stay flexible
Market demand may vary over the year, so plants need to adapt to different volumes much more today than they had to in the past. They also need to adapt to different cheese types and formats. The traditional Euroblock size is still, by far, the most traded format globally. And it is still growing. However, variety in cheese types and formats is also becoming increasingly important. Jurjen explains:
“We see a growing demand for different cheese types. And it’s not only a matter of taste, but also cheese made from different milk types like, for instance, Gen-Free milk, milk from cows grazing outside and biological milk. Not long ago, cheese plants used to produce the same cheese over full days, but now it is quite common that they start with five batches of Gouda, then move to an Edamer type, and then something else ... and it’s consumer demand driving this. They want more to choose from. As a system supplier, we have to design complete cheese lines that are able to handle these varieties and make sure the flexibility requirement has a minimum effect on the efficiency of a cheese production line.”
Efficiency and sustainability go hand in hand
With more uptime – which results in fewer cleaning cycles – and a reduced amount of waste streams, you get a more sustainable production process. This has a direct link with efficiency – the more sustainable you are, the lower your operational costs are.
An efficient cleaning process benefits both the environment and bottom lines.
“The curd brings money into your wallet, so the less curd remains in the machine before the CIP process, the better it is. This also enables a shorter cleaning process and reduced consumption of electricity, water and chemicals.”
On top of that, short cleaning windows result in more uptime – which helps bring the operational costs to a minimum.
For many industrial cheese producers, the whey proteins have become the most valuable part of the milk. To make sure no whey is spoiled or downgraded to animal feed, Tetra Pak developed the Whey Tray system. This is another great environment- and profit-friendly invention, which is used to press and form a rind around the cheese and at the same time produce high quality whey. The cheese pressing moulds are positioned in whey trays, where the whey is collected during the pressing process. After a batch of cheese is pressed, the moulds and the trays are cleaned in a rinsing machine. Then the pressing process starts all over again with clean moulds and trays! One of the benefits is that the pressing units are not fouled with product remains, so they do not need to be cleaned on a daily basis.
The future is digital
Consumers increasingly seek out brands with transparent supply chains and ethical production. Natural ingredients and sustainable practices also affect consumer choices. Better control of milk composition, cheese quality and production parameters are some of the benefits digital tools bring to producers. Time-consuming manual activities to analyse production data for fine-tuning can now be done automatically. Digitalisation also opens up to full traceability of the entire supply chain – from cow to consumer – with verifiable data of everything from animal welfare to storage.
Digitalisation enables efficiency and, as a consequence, increased profitability. Accurate, real-time information on incoming milk streams – like the protein/fat ratio we talked about above – makes production planning easier.
These opportunities have encouraged Tetra Pak to develop the Line Optimization Module (LOM). The LOM can be equipped with a variety of different modules to improve our customers’ efficiency, traceability, production planning and a lot more!
There are LOM modules available to help cheese producers trim moisture and weight deviations to a minimum. Furthermore, quality control points can be integrated in the LOM for active process control. This helps make the cheese line processes more robust, increase product quality and secures efficient production.
Interested in discussing your semi-hard cheese operations with us?
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