Pressurized Vs Gravity Machines
Ice cream machines essentially do three things, freeze mix, add air to the product and dispense the product. The amount of air in ice cream is called overrun which is relevant to the overall product that you serve. Overrun is measured in percentage and it's basically the amount of air added to the product relative to the amount of mix added. For instance, if you add one gallon of mix to the machine and it dispenses 1.5 gallons of finished product, then the overrun is 50%. Pressurized and gravity machines each produce their own percentage of overrun, which is an important consideration when you're looking to purchase or lease and ice cream making machine.
When it comes to pressurized VS gravity equipment, we learn that there is no wrong answer when it comes to using one or the other. It merely depends on which machine is better for your situation.
At first glance, you'll notice the gravity machine has a hopper on top where you pour the mix where as the pressurized machine has a cabinet at the bottom where the mix is stored and pumped from. The gravity machine uses gravity flow to get the product into the chamber and uses a carburetor tube to control the amount of air (overrun) that gets added to the mix. This tube also meters the amount of mix that goes into the freezing cylinder. The disadvantage is that you can't control the specific percentage of overrun, therefore the finished product might fluctuate in consistency. With a gravity machine you're getting a low overrun percentage between 25%-40%, meaning the finished product will be wet and heavy.
- Mix is dispensed through the top of the machine
- Uses gravity to pull the mix into the freezing cylinder.
- Overrun is tube regulated
- Small amounts of product inconsistency
- Low overrun
With a pressurized machine the product is measured with an air meter. This means the machine produces a consistent product every time. Pressurized machines can hit around 50%-60% overrun, so you're going to produce a product that's light and fluffy and can stand up on a cone. The advantage here is a more consistent product for your customer and better control of food cost.
- Mix is pumped from the bottom
- Uses pumps to pull the mix into the freezing cylinder
- Air metered - total control of product overrun
- High amount of product consistency
- High overrun
There are other factors that can help determine which machine is right for your store. For example, if you're a small ice cream shop or secondary store that that charges by weight then a gravity machine might be right for you. What's more, you need to consider additional factors like maintenance of the machine, how much down time it requires for cleaning and of course price.
- Low Overrun - 25% - 40% - Wet and Heavy
- High Overrun - 50% - 60% - Fluffy and Light