Soft Serve – Common Errors

Soft Serve – Common Errors

Training :: Soft Serve :: Common Errors and How to Avoid


Freeze Ups

Freeze ups lead to issues which prevent you from serving product.  In severe cases, expensive components can be broken or damaged and cause extensive down-time.

Freeze ups are caused primarily by one of three things (see below for further details): 
  1. Starved Cylinder – Insufficient product entering the cylinder
  2. Product Issues
  3. Improper Cleaning


Starved Cylinder 

Cylinder starvation occurs when the product level in the freezing cylinder is too low.  Usually, this happens one of three ways:  improper priming when first adding product to the machine, running machine in low level or a blockage preventing product from entering the freezing cylinder.
  1. Improper priming :: If the machine was initially frozen with an improper prime level, the product could freeze up at any time during normal operation depending on serving size, brix level, etc.  These freeze ups can occur even when not serving a lot of product.
  2. Low level :: Do not open the dispensing handle and serve product if the product level in the hopper is low.  If the red light or low-level indicator is illuminated, fill the hopper immediately. 
  3. Blockage :: If the cylinder is still starved, and the above two issues are definitely not the issue, you may have a blockage preventing product from the hopper from making its way to the freezing cylinder. 
If a freeze up occurs, power OFF the machine and do not use until product thaws.  Damage may occur if you attempt to run the machine while product is frozen.

On all machines, verify the following:
  1. Inlet from hopper to freezing cylinder is clear and clean.  Use brush to clean this area while the motor is off
  2. Product does not have any particulates which may cause a blockage.
  3. Freezing cylinder was properly primed when product was added using the prime plug on the front door
On gravity fed models specifically, also verify:
  1. Air tube is inserted properly with the product inlet hole (on the side of the air tube) is at the bottom
  2. Air tube is cleaned and free of product which may have hardened.  Use the specific brushes to clean air tube product inlet (side to bottom) and air inlet channels (top to bottom) so they are clear.  The air tube should be cleaned and sanitized multiple times daily.
On air pump/pressurized models specifically, also verify:
  1. Air inlet holes (two small holes on either side of outer shell) on the air pump are clear and clean.  Product level must be below this area for the pump to work properly.  
  2. Air pump was primed.  During cleaning, with the injection tube removed from the front of the air pump you should see a steady stream of product spraying out of the pump before freezing.
    Warning:  Do not disconnect injection tube after entering freeze mode.  This tube is under high pressure and may shoot out of the machine if disconnected once the pump has operated.  Properly clean and disassemble the machine to verify proper priming
  3. Air pump is assembled correctly, clean, and free of blockages or hardened product.  All parts in the exploded view of the air pump assembly must be disassembled, cleaned, and replaced quarterly or when damage or imperfections are noted.  
  4. Air pump shell seal/gasket is installed and has no knicks or imperfections.  Light lubrication is required for an air-tight seal.
  5. Air pump shell is tightly fastened
  6. Product cannot have any particulates which may cause blockage in the suction tube.  Product should be strained if necessary to avoid particulates.

Product Issues

Product must be premixed and prechilled prior to adding to a soft serve machine.  Ensure there are no ice chunks, particulates, unmixed powder, or product separation prior to adding to machine.   You cannot use the hopper and hopper agitators to mix product inside the machine.  This will lead to improper ratio of products in the freezing cylinder and will cause freeze ups.  

Soft serve machines require a special recipe and ratios of sugars, stabilizers, and fats to run properly.  It is important that you purchase a product mix which is manufactured specifically for “soft serve” machines.  Some ice cream and gelato mixes are formulated for batch freezers or other uses - they may not work in a soft serve machine.  If you are making your own mix, it will take trial and error and research on your end to get a good stable product which will work well.  Some custom products may only last one day in the machine before needing to be replaced.  Learn how to use the machine with a known product first so that you know what to expect and have a baseline of success.

Soft serve products require a specific Brix level.  Please see the  Soft Serve Brix Level article for more information on how to check your Brix level.  Various things can affect the Brix level of your product, including sugar content, alcohol content, other dissolved solids such as flavorings, etc.  

If your Brix Level is too high or too low, or if your brix level varies between batches, you will experience a variety of product quality and machine issues.  As Brix level increases, the freezing temperature of the product decreases.  As the Brix level decreases, the freezing temperature increases.  This means that as the Brix level increases, the viscosity setting must also change.  So, if the Brix level of your product changes, and you do not change your viscosity accordingly, you may end up with soft and runny product or a freeze-up.    Spaceman does not advise regularly changing viscosity to chase Brix levels.  Instead, it is far easier and recommended to achieve a consistent product mix and maintain a consistent Brix level between batches.


Cleaning and Maintenance

Proper cleaning and maintenance of your machine will ensure smooth and consistent operation for many years to come.  It is important to follow the cleaning instructions provided in the manual exactly.  More than 50% of maintenance bills, freeze ups, and consistency issues can be prevented by proper cleaning. 

Rinsing the machine nightly with water or sanitizer and then turning off is not a substitution for proper cleaning, is not food-safe, and can be harmful.  Most models include a standby or nighttime refrigeration mode for safe product storage over-night.  If you leave the machine in the off position without fully cleaning and disassembling your machine, you are leaving food contact areas exposed to high temperatures and ambient conditions which will allow bacteria to grow. 

A full cleaning including removing the front discharge door, beater and scraper blades, and rear drive shaft and gasket must be completed according to the manual and video instructions.  When re-assembling the machine after cleaning, proper lubrication will ensure longer life on the rear shell bearing, gears, motors, and belts, as well as the wearable parts.  It will also help to prevent leaking. 

All wearable parts should be replaced quarterly.  Condenser fans should be cleaned at least two times per year and belts should be during that time.  If the condenser fans are clogged up or dirty it will prohibit your machine’s ability to remove heat and freeze product.  This will lead to longer freeze and recovery times, poor product consistency, constant machine running, excess hot air discharged from machine, and high electricity costs.
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