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When talking with an equipment manufacturer to scale up your food production business. The question might come up. Are you planning to run continuously or in a batch-like manner?
Often, you’ll use some form of continuous production if you’re planning on running 24/7. Batch processing is oftentimes used for smaller runs that only run for a couple of hours per day.
- Batch vs. Continuous production
- Batch processing: pros & cons
- Advantages & disadvantages of continuous processing
- Continuous vs batch processing in food production
- Get started
Batch vs. Continuous production
In continuous production an ingredient travels through the process without “stopping”. It goes from one step to the next, and so do all the other ingredients. Ingredients don’t have to wait for a step to be completed for other ingredients. As soon as it’s done, it goes into the next step.
In a batch process on the other hand, all ingredients first go through step 1, then they jointly start step 2, etc. They might all be mixed first, then they’re all baked and then they’re all cooled down.
An example: french fry production
Let’s have a look at the production of french fries as an example.
In a continuous process, you might have a large belt onto which potatoes are dropped continuously. This belt then feeds the potatoes into a cutter which cuts continuously. Once cut, the potato drops into hot oil through which it is transported using another conveyor belt. At the end of the oil bath, it leaves the oil and travels into a freezer, again, on a belt. During the whole time, you’ll have potatoes in every step of the process. Some just entered the frying oil, others are almost done frying, yet others have just entered the cooling tunnel, or are mid-way freezing.
In a batch process on the other hand, you’ll take a bag of potatoes and fill this into a cutting machine. You cut all the potatoes before collecting them in a bin. The potatoes are then dropped into hot oil. Once they are done frying, they’ll all be taken out at the same time. They are then spread onto a tray and placed in the freezer to be frozen.
Notice how all potatoes of one batch start and finish each step at the same time, whereas for continuous processing they all travel through by themselves.
Another example: bread bakery
We can do the same for a bread baking process. In a batch process, all ingredients for a batch will be added to a mixer which then kneads the dough. Once kneaded, it is all taken out and left to proof. The proven dough is then portioned. After another proof, they’re all placed in the oven at the same time, and baked.
In a continuous bread making process on the other hand, things move continuously. Mixing isn’t done in a bowl, but in a screw with product entering on one end and leaving on the other continuously. Same for baking which probably happens on a conveyor belt that moves through a hot oven. At any point in time the oven contains bread that only just entered, bread that’s almost done and anything in between.
An intermediate: semi-batch
Some processes aren’t purely batch or continuous. They are a mix of the two. This means that part of the process is a batch process whereas other parts are continuous.
As an example, maybe the bread dough is made in a bowl, in a batch-wise manner. The dough is then dropped into a machine that shapes the dough into smaller pieces. From here on, the dough pieces move through the rest of the process continuously. By the time that first portion of dough has been cut into all its pieces, the next batch is ready which can then enter the rest of the process.
Batch processing: pros & cons
The major advantage of batch over continuous processing, is the fact that batch processing tends to be more flexible. Every batch can be slightly different. You could make a different flavor, slightly different consistency, color, etc. You simply remove the previous batch from your equipment, and you’re good to go to make something else.
Natural variability, easier to adjust
Most food ingredients aren’t identical time and time again. As such, you might need to adjust your process slightly, depending on your incoming ingredients. This is easier to do in a batch production process than it is in a continuous process.
Cheaper process control
Costs for controlling the process tend to be lower. You might be surprised to learn how expensive accurate continuous feeding and weighing equipment is. For a batch process you can use more ‘regular’ equipment.
A batch process tends to need more manual labor than a continuous process. However, this is not a given.
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Advantages & disadvantages of continuous processing
The big advantage of continuous processing is the consistent continuous quality of the product. It will be pretty much identical no matter when it’s made on the line. That said, it is less flexible than a batch process, it is often harder to change between those different muffin flavours.
Another big avantage is that once the process is running, there’s not a lot that has to be done anymore. No cleaning of bowls in between, the process will keep running. This requires less labour for production. However, investment costs are often a lot higher than for a batch process. Whether or not this will make sense mostly depends on the volumes you need.
Continuous vs batch processing in food production
When choosing for batch vs continuous processing there are several aspects that will play a role, the most important probably being scale. A continuous process really only makes sense if you need enough product to run a continuous line for longer stretches of times. A continuous process might take a while to start and stop, but once it’s running, it just keeps on going. So, if you only need 1 hour of production at a time, a continuous process doesn’t make sense. In that case a batch process will probably suit you better.
Whether or not your scale is large enough greatly depends on your production volume, the process, the flexibility you need within the process. Do you only make 10.000 vanilla cupcakes, or do you make 2.000 cupcakes of 5 different varieties? Chances are that the 10.000 vanille cupcakes are more likely to be suitable for a continuous process than the 2.000 cupcakes of 5 varieties.
Besides scale a lot of other reasons will influence your choice, we’ll list a few:
- Flexibility: have you set your recipe, or are you still tweaking and changing things all the time? Continuous processes, once designed, are often less flexible
- Variation in ingredients: how stable are your ingredients? Do they vary a lot, depending on the season, supplier? If so, you might want to control that some more before looking into continuous processing.
- Investment: starting up and still have to find prove in the market? Batch is most likely the way to go, the lower investments will make it easier to start. That said, if you work with another company as your external manufacturer, things might be different.
As with most articles in this scaling up series, the theory is not all. You have to start collecting data, get digging and start learning. Hopefully, this article has given you to first direction for your decision on batch vs. continuous processing (or has finally made clear what the differences are). Do leave a comment or send a message if the article has been helpful or if you have further questions!