For a pneumatic membrane press in a craft cidery, a 7.5 to 11 kW 4-in-1 screw compressor covers most cases: the K 75 delivers 1.1 m³/min at 8 bar, the K 110 1.7 m³/min. The right choice depends on three figures from the press: its tank volume, the maximum membrane pressure and the time you want for the pressure to rise. If bottling runs at the same time, add the two together.
The air needs of the rest of the cidery, from the washer to the bottling line, are covered on our page on compressors for breweries and cideries.
Does the press already have its own compressor?
Start with the manual. Some pneumatic presses come with their own compressor, others need an air supply from the workshop. If it is built in, your workshop compressor only serves the other machines. If not, the press data sheet gives the supply pressure and often the consumption per cycle.
The calculation, step by step
When the data sheet gives no flow, you can estimate it. To inflate a membrane, you need a volume of free air roughly equal to the inflated volume multiplied by the gauge pressure in bar.
Step 1, the volume. Take the volume of the press tank. It is an upper bound: at the end of a pressing, the membrane fills most of the tank, and the rest is pomace.
Step 2, the pressure. Take the maximum membrane pressure given by the maker.
Step 3, the rise time. The press program raises pressure in stages. Use the fastest rise in the program.
Step 4, the margin. Add 25 %, as our configurator does.
Example of a 1,500 litre press, with a membrane pressure of 2 bar for the example and a rise in 3 minutes:
- free air per inflation: 1,500 × 2 = 3,000 litres
- flow during the rise: 3,000 ÷ 3 = 1,000 l/min
- with a 25 % margin: 1,250 l/min
The K 75 (1,100 l/min at 8 bar) would be too tight. The K 110, 1.7 m³/min at 8 bar, holds this flow with reserve. Between two rises, during the holding and crumbling phases, consumption drops: the 340 L receiver and variable speed do the rest.
This calculation gives an order of magnitude. If the press data sheet states a consumption, that figure wins.
Which model for your cidery?
| Situation | Need with margin | Model |
|---|---|---|
| Small press, slow rise, press alone | up to 1,100 l/min | K 75, 420 L receiver |
| Press from the example, alone | around 1,250 l/min | K 110, 1.7 m³/min at 8 bar |
| Press and bottling at the same time | above 1,700 l/min | K 150, 2.2 m³/min at 8 bar |
Example for the last row: the press at 1,000 l/min plus a bottling line at 500 l/min makes 1,500 l/min, or 1,875 l/min with the margin. The K 150 covers it.
What if the press only runs six weeks a year?
That is the case for many cideries. Sizing the compressor on the apple season means paying for an oversized machine the rest of the year. Another option is a compressor chosen for bottling and the year-round machines, topped up during the season by a hired screw compressor. Our rental range runs from 5.5 to 132 kW.
Dry air, frost and filtration
- Water in the membrane. Humid air condenses in the membrane and in the press pipes. The refrigerated dryer built into the K series deals with it.
- Cold. Cider season falls in autumn and winter, often in barely heated buildings. A refrigerated dryer must be installed in a frost-free room, and water left in a cold pipe can freeze: keep the compressor and its dryer in the warm. Our article on which air dryer to choose explains the limits of each technology.
- Filtration. In normal operation, the air stays behind the membrane and does not touch the juice. But a membrane can crack. Our compressors are lubricated: add fine filters on the press supply and define the air class under ISO 8573-1 with our technicians and the press maker.
- Pressure. Set the compressor to 8 bar. The press has its own regulator for the membrane: do not set the compressor to the membrane pressure.
Before the season
Service the compressor before the first apples, not in the middle of the season. First service at 500 hours, then every 1,500 hours, with a reminder on the controller. Our service kits group the parts for each model. Also check the drain and line filters after the summer shutdown.
The same reasoning applies to a grape press, which we cover on our page on compressors for wineries. For your cidery, send us the press data sheet and your list of machines with a quote request.
For your trade: Compressor for breweries and cideries.