How To Fix Keurig Not Brewing A Full Cup: 3 Simple Solutions

Mike C
Written By Mike C

I've been writing about coffee and espresso machines for 3 years. My goal is to provide you with helpful content that you can trust based on my own personal experiences, information from manufacturers, and tips and tricks I've gathered from other coffee and espresso machine users.

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How To Fix Keurig Not Brewing A Full Cup: 3 Simple Solutions

A Keurig not brewing a full cup of coffee usually means there is a blockage somewhere in the brewer that is interfering with machine performance. There are a few common problems that can prevent a Keurig from making a full cup. Keep reading to learn what they are and how to solve them. You’ll want to have a glass measuring cup handy.

Why Is Keurig Not Brewing A Full Cup?

A Keurig not brewing a full cup is usually caused by one of these 3 reasons:

  • Limescale buildup is causing blockages in the Keurig’s internal water pipes
  • Debris or limescale is clogging the exit valve at the bottom of the water tank
  • Coffee grinds have built up around the entrance or exit needles and are blocking water flow

Fortunately, there are easy solutions to all of these causes. Keep reading to learn more.

3 Ways To Fix A Keurig Not Brewing A Full Cup

Solution 1: Descale To Remove Internal Blocks

If you found calcium buildup in your water tank, it is likely inside your machine too. As the water used to brew your K-cups travels through your brewer, it leaves minerals behind that cause limescale to buildup inside your machine. Eventually this buildup can get big enough to cause blockages that result in your Keurig not making a full cup.

You should descale every 3 to 6 months, even if you are using a water filter. If your tap has “hard water,” meaning it contains a high level of minerals, then you should descale your brewer more often. If you are unsure if you have hard water, you can get a low-cost testing kit.

Keurig makes its own descaling solution that works with all models. The safe formula has no odor and acts fast to remove mineral buildup with gentle citric acid. Once you have the descaling solution, follow these instructions to descale your Keurig. If you’ve had your machine for more than 6 months and never descaled, or if you have very hard water, you may need to run this process at least 2 times.

Solution 2: Clear Buildup Around The Water Tank Valve

keurig water filter holder

Water has to be able to freely flow from your tank into the machine. If there is any mineral buildup around the exit valve, the machine may not be able to pull the amount of water needed to brew a full cup. Here’s how to assess this issue and fix it:

  1. Empty the water tank. Remove the water filter holder.
  2. Flip the the reservoir over. Locate the nozzle with the spring. Take something dull like a the eraser end of a pencil and try pushing the spring down a few times. If it moves with ease, you can rule out any issues with that piece.
  3. Put the tank back on the machine. Fill it with about two to three inches of water.
  4. Grab a turkey baster. Suck up a little of the water from the tank.
  5. Squirt the baster directly into that top side of the black nozzle where the water should exit the tank. Repeat this several times, working all the way around the nozzle two or three times.

If you start to see particles floating up from the nozzle, this is calcium buildup that was causing the block.

Solution 3: Unclog The Needles

keurig needle blockage resulting in keurig not brewing a full cup
keurig needle blockage resulting in keurig not brewing a full cup

When you brew a K-cup, there are needles inside your coffee maker that make two holes in the pod. This allows hot water to pass through the capsule. The coffee grounds can get stuck around the needle and eventually become dry and hard. This is especially likely to happen if you don’t discard your pods soon after brewing. As a result, the ground coffee build up starts to block the water flow inside your Keurig, potentially resulting in the Keurig not brewing a full cup of coffee.

Cleaning your Keurig needles is easy. All you need is a paper clip.

  1. Straighten one end of a paper clip.
  2. Turn off the brewer and unplug it and remove the water reservoir.
  3. Grab the sides of the pod holder and remove it from the brewer by gently pulling away.
  4. Press the button on both sides to separate the holder from the housing. Push the lever to show the exit needle, then hold it down while flipping the holder over.
  5. Insert the straight end of the needle and then move it around in a circle a few times. Rinse the pod holder with water and set it aside.
  6. Open the handle and look underneath to see the top entrance and exit needles. Insert the paper clip in each and move it around to clean.
How To Clean Keurig With Paper Clip

How To Check If Your Keurig Is Now Brewing A Full Cup

Once you’ve done any one more of the above solutions, you should check to make sure your Keurig is brewing a full cup. You’ll need a measuring cup. Without a K-cup in the chamber, run an 8 oz hot water cycle into a measuring cup. If the water volume measures 8 oz, you’ve figured out why your Keurig was not making a full cup of coffee. If not, try any of the remaining solutions.

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