Ice machine maker sizing: why most venues buy one too small

Every summer, venues run out of ice. Almost always the machine is working correctly and the problem is that it was sized on the number printed in the brochure.

That number is measured in a lab at 21 degrees ambient with 10 degree incoming water. A Brisbane bar in January has 32 degree air behind the counter and mains water arriving at 25 degrees. Under those conditions, a machine rated at 100kg per day will produce somewhere between 65 and 75kg.

Size on the derated figure, not the brochure figure.

Working out what you need

Rough consumption benchmarks:

• Bar or pub: 1.0 to 1.5kg per customer per day
• Restaurant: 0.5 to 0.8kg per cover
• Cafe with iced drinks: 0.3 to 0.6kg per customer
• Fast food or takeaway with fountain drinks: 0.8 to 1.2kg per customer
• Hotel with function rooms: add 1kg per function guest

Take your busiest day of the year, not your average. A venue that does 300 customers on a normal Saturday and 700 on Melbourne Cup day needs to survive the 700.

Then apply the derate. If your peak demand is 250kg and you are in a hot kitchen with warm mains water, you need a machine rated around 340 to 380kg per day.

The bin is half the answer

Machines are sold as either self contained with an integrated bin, or as a modular head that sits on a separate bin.

Bin capacity buys you peak capacity without buying a bigger machine. A 200kg per day machine on a 150kg bin can deliver 350kg across a busy evening, because the machine spends the quiet morning filling the bin.

That is almost always cheaper than buying a machine big enough to make it all in real time. Work out your demand curve, not just your daily total.

Bear in mind ice in a bin melts. A well insulated bin loses around 1 to 2 percent per hour. A bin filled Friday night will have lost a meaningful amount by Saturday lunch.

Ice types and where they belong

Full cube or dice. The standard. Slow melting, low dilution, good for spirits and general bar use. Roughly 22mm cubes.

Half cube. Packs more densely into a glass so it looks fuller and displaces more liquid. Popular for fountain drinks and takeaway. Melts faster than full cube.

Gourmet or top hat. Slow melting, clear, heavy. For premium spirits service where the ice is part of the presentation.

Nugget or pellet. Soft, chewable, absorbs flavour. Loved in healthcare and in venues selling smoothies and soft drinks. Higher output per kilowatt than cube ice.

Flake. Soft, wet, moulds around product. For seafood displays, salad bars and food presentation, not for drinks.

Block. Specialist. Cocktail bars carving their own.

Most venues want cube for the bar and flake if they display fresh product. Trying to serve both from one machine does not work, so budget for two if you have both needs.

Air cooled, water cooled or remote

Air cooled is the default. Cheapest to buy and run, but it rejects heat into the room and needs proper clearance. In a hot back bar this is exactly the wrong place for it, and it is why so many under bar machines underperform.

Water cooled uses mains water to reject heat and then sends it down the drain. It works in hot confined spaces but the water consumption is significant and in some council areas it is restricted. Check before specifying.

Remote condensing puts the hot side outside. More expensive to install, quieter inside, and it stops the machine fighting the room. For a busy venue with a hot back of house, this is usually the right answer despite the install cost.

Water quality decides the service bill

This is the item most operators discover the hard way.

Australian mains water varies enormously in hardness. Hard water scales the evaporator plate, which reduces output, increases cycle time, and eventually requires a descale that costs several hundred dollars in labour.

Fit a proper ice machine filter with scale inhibition, not a generic carbon cartridge. Carbon improves taste and removes chlorine. Scale inhibitor is what protects the machine. You want both, and most purpose built ice machine filters do both.

Change the cartridge on the manufacturer's schedule, usually every six months. Put it in the calendar. A filter left in for three years is worse than no filter.

Cleaning is a food safety obligation

Ice is a food. Ice machines grow biofilm and mould in the water reservoir and on the distribution tubes, and this is a routine finding in council inspections.

Most manufacturers specify a clean and sanitise cycle every three to six months. It takes about an hour and uses a nickel safe cleaner followed by a sanitiser. Either train a staff member or put it on a service contract, but do not skip it.

Signs you are overdue: ice tasting off, cubes cloudy or irregular, slime visible in the reservoir, or output dropping without any other explanation.

Placement and services

Leave the specified clearance, usually 150mm at the sides and rear on an air cooled unit. Confirm the machine is not drawing its intake air off the back of a fridge condenser, which happens constantly in tight back bars.

You need a cold water supply, a dedicated power circuit, and a floor waste or a gravity drain. Ice machines produce drain water continuously and a condensate pump on an ice machine is a failure point that will eventually flood something.

Finally, check the noise rating if the machine is near a dining area. A harvest cycle dropping 5kg of ice into a steel bin is not subtle, and in a quiet restaurant it carries.