K40 Partial Cup Brewing

Photo of a K40 coffee machine




I have to run it twice to get a full cup of coffee.


William wrote to us the other day about his K40 and the partial cup brewing that it is now producing. This type of fault is quite common with the classic range of Keurig brewers as oppose to the newer 2.0 machines, that do not seem to suffer from this as much (although we did write about this yesterday in replying to an email from Rosie).

The most common cause of partial cup brewing is a failure in the brewer’s air pump. The purpose of this pump is to build the correct air pressure in the boiler unit. Once the boiler has heated the water to the correct temperature the air pressure, built by the air pump, is used to force this water from the boiler, across the top assembly, into the entry needle and then into the waiting K Cup in the portion pack holder. Then of course this makes the coffee that ends up in your coffee cup.

Photo showing you a Keurig air pump for a B60

We have found the most common cause of faults with air pumps is moisture damage. This can cause the pump itself to develop rust or corrosion build-up. Moisture often comes from leakage of the solenoid unit (that sits right next to the air pump in most Keurigs – as seen in the photo above). So as the pump is affected in the air pressure if can pump, not as much coffee ends up in your coffee cup. In the case with William it’s taking two brewing cycles to get enough volume through.

Solution – “Keurig Burp”

The easiest thing to try is commonly called the Keurig Burp or Slap. This provides a short jolt to the area around the air pump with the aim to “encourage” the air pump back into action if the fault is a build-up of deposit that is putting it under strain and therefore unable to build the correct air pressure.

Our short guide here will take you through the steps to try this solution. Do bear in mind that this approach often does work, but not always, and does tend to be temporary. The more permanent solution being an air pump replacement.

Solution – Air Pump Replacement

If the Burp approach hasn’t worked then the next step is to get the pump replaced. This does take a bit of work and time, but little cost. For around $10 a pump can be purchased from ebay or amazon.

Photo of an air pump for a Keurig brewer

Check out our guide that looks into detail the partial cup brewing problem, and this guide also references our other guide on how to replace the air pump. This takes you through what tools you need, the part to buy and a description and photo of each step.

To encourage you with having a go at fixing your Keurig brewer please read our recent post and email from Terri. For $35 (she had to replace three parts) she got her B70 back working perfectly. This is a coffee machine that costs around $225 new. For a little time and effort this was a huge saving for Terri … we were most impressed.

Photo of a Keurig B70 coffee machine