Determining how much syrup a pump dispenses depends on the type of pump and the viscosity of the syrup. Commercial syrup pumps are calibrated to dispense a consistent amount with each pump, typically between 1/8 oz to 1/4 oz per pump. Thicker syrups like chocolate or caramel will dispense less per pump than thinner syrups like simple syrup. For home use, the amount dispensed can vary more depending on the pump mechanism and syrup thickness.
Standard Syrup Pump Sizes
Commercial syrup pumps for coffee shops and restaurants are made to standard sizes that dispense between 1/8 oz (3.7mL) to 1/4 oz (7.4mL) with each pump. Standard pump sizes include:
- 1/8 oz (3.7mL) pump
- 1/6 oz (5mL) pump
- 1/4 oz (7.4mL) pump
The most common size is the 1/4 oz pump because it dispenses enough syrup for a typical serving without requiring too many pumps. The smaller 1/8 oz and 1/6 oz pumps are used for smaller drink sizes or very concentrated syrups that only need a small amount per serving.
Factors Affecting Syrup Volume
While syrup pumps are designed to dispense a consistent amount, there are some factors that can affect the actual volume dispensed:
- Syrup viscosity – Thicker syrups like chocolate or caramel will dispense less per pump than thinner syrups like simple syrup. The viscosity impedes the syrup’s flow through the pump mechanism.
- Syrup temperature – Colder syrup temperatures increase the thickness, decreasing flow. Warmer temperatures make syrup thinner.
- Pump quality – Better commercial pumps have mechanisms to dispense consistently regardless of minor viscosity changes. Cheaper pumps are more affected by thickness.
- Pump wear – Old, worn out pumps may leak and not dispense a full 1/4 oz per pump.
Measuring Syrup Dispensed
To empirically test how much a syrup pump dispenses, you can measure the syrup dispensed over multiple pump cycles. Here is a simple experiment to measure pump volume:
- Place a measuring cup on a scale and tare/zero it.
- Pump the syrup 10 times directly into the cup, being careful not to spill.
- Check the measured weight on the scale.
- Convert the weight to volume based on syrup density. For example, corn syrup has a density of 1.3 g/mL.
- Divide the total volume by 10 to get the average volume per pump.
Repeating this test 5-10 times will improve accuracy. Results can vary +/- 5-10% for the average volume per pump.
Example Measurement
Here is data from an example test measuring 10 pumps of simple syrup, with a density of 1.3 g/mL:
| Test # | Weight (g) | Volume (mL) |
|---|---|---|
| 1 | 32 | 24.6 |
| 2 | 33 | 25.4 |
| 3 | 31 | 23.8 |
Averaging the 3 tests gives an average volume per pump of 24.6 mL. So this pump dispenses about 1/4 oz (7.4 mL) per pump.
Tips for Consistent Dispensing
Here are some tips to help get consistent syrup dispensing from pumps:
- Use room temperature syrup. Refrigeration will thicken syrups.
- Replace worn out pumps that may leak and under-dispense.
- Calibration testing can identify bad pumps.
- When filling pumps, bleed air bubbles out to prime pump.
- Gently swirl bottle before installing to mix syrup consistency.
- Keep syrups properly sealed to prevent evaporation or contamination.
- Clean pumps regularly following manufacturer instructions.
Types of Syrup Pumps
There are a few main types of commercial syrup pumps used in coffee shops and restaurants:
Push Button Pumps
These operate by pressing a button or lever, which uses a spring mechanism to draw up and dispense a consistent syrup amount. Easy press-dispense operation.
Twist Pumps
A twist knob draws up and dispenses the syrup with a twisting motion. Twist direction dispenses, opposite direction resets.
Trigger Pumps
Popular for bartending, these use a trigger lever to dispense syrup. Allows hand to stay on the trigger for rapid pumping.
Rotary Pumps
Rotating a dial on top increments an internal metering mechanism to dispense a preset amount of syrup per rotation.
Electric Pumps
Electric power automates the pumping mechanism. Dispenses with the press of a button. More consistent than manual pumps.
Cleaning and Maintenance
Regular cleaning and maintenance helps syrup pumps dispense properly with consistent volumes. Cleaning steps include:
- Rinsing pumps in hot water to dissolve syrup residues
- Disassembling pumps and cleaning internal parts
- Using commercial pump cleaning solutions to break down residues
- Sanitizing with food-safe sanitizers
- Fully air drying pumps after cleaning
- Routine replacement of o-rings, seals, tubes, and other wear parts
Consult your pump manufacturer’s instructions for proper cleaning methods and frequency.
Troubleshooting
Issues like leaks, clogs, inconsistent dispensing, or failed dispensing can indicate a need for pump maintenance. Try these troubleshooting steps:
- Clean pump thoroughly following manufacturer instructions
- Inspect for damaged parts and replace as needed
- Make sure inlet tubing is not obstructed preventing syrup flow
- Ensure any air bubbles are bled out of the pump mechanism
- Confirm pump is properly assembled and tightened after cleaning
- Test with water only to isolate potential syrup viscosity issues
If problems persist after troubleshooting, the pump may need rebuilding or replacement.
Conclusion
With standard commercial pumps dispensing between 1/8-1/4 oz per pump, calculating syrup amounts is straightforward based on number of pumps. Viscosity, temperature, pump quality and wear can affect the volume dispensed. Testing pumps is needed to determine precise amounts dispensed over multiple cycles. Keeping pumps clean, well maintained, and replacing at signs of wear helps ensure consistent volumes are dispensed. Knowing your syrup pump sizes and using best practices makes syrup portioning easy.
