You can reset most Keurigs by holding the power button, 8oz, and 10oz buttons for 5 seconds. ● To reset the Keurig Classic and Keurig Slim, press and hold the medium, large, and auto-shut-off buttons for 10 seconds. ● To set the Keurig Compact, hold the power button, press the smallest button, medium button, and largest button in order. ● To reset the Keurig K Supreme, hold down both arrow buttons until you reach the setup menu, click next, then perform a 'Factory Reset.' ● To reset the Keurig Mini, turn the machine off and on, leave it for a few minutes, then hold the brew button for 3 seconds.

Why Is My Keurig Not Brewing A Full Cup? (How To Fix)

Keurig not brewing a full cup of coffee? That's not supposed to happen, and it's usually a sign that something is wrong.

Still, don't rush out and buy a new machine just yet. I've had the same issue, and it's perfectly possible to fix it yourself.

In this guide, I'll help you find out why your Keurig isn't producing a full cup of coffee and show you how to fix it fast.

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Can’t Get A Full Cup Out Of Your Keurig? (3 Common Reasons & Fixes)

1 K cup equals 1 full cup of coffee, or at least that's how it should work. Let's have a look at a few common problems that might be giving you a smaller cup of coffee.

Learn More - How To Keurig Machines & K-Cups Work?

1. It’s Time To Clean The Water Valve

Keurig coffee makers have a plastic valve at the bottom of the reservoir. If this becomes clogged, it will stop the water flow in your device.

This usually happens when water is left in the tank too long, allowing dirt and bacteria to build up.

It can also be caused by a calcium buildup which requires a descale (I'll go through that process in a minute).

It’s easy to fix. You’ll just need a turkey baster (or a squirting syringe alternative).

Clean around the water reservoir.
Empty the water reservoir, remove, and clean it. Focus on the valve at the bottom and remove any debris blocking it.
Force air into the valve.
Fill the water reservoir ⅓ with filtered water. Take your turkey baster or syringe and suck some water in. Push the tip of the baster or syringe into the water valve and firmly press down. This will force water into the valve, loosening any coffee grounds, dirt, or debris.
Repeat
You should notice some air bubbles come up and dirt starts to come out from the water pump into the water reservoir. Repeat the process with the syringe until the water reservoir is filthy. When the water is dirty, empty the reservoir.
Do a water-only brew.
Do a water-only brew with an empty K cup holder. This will flush out the dirt and any coffee residue from the system.
Test the Keurig
Try brewing coffee again. If the Keurig machine isn't brewing a full cup, repeat the process until the valve is clear and it can brew a full cup.

Learn More - How To Prime A Keurig

2. Your Machine Needs A Descaling

Limescale and mineral deposits will naturally build up over time, particularly in areas with hard water.[1]

These deposits can cause blockages within your Keurig machine, preventing water from flowing and brewing a full cup of coffee.

Descaling your Keurig coffee equipment is straightforward. All you need is some descaling solution or a half cup of white vinegar to make your own descaling solution.

Mix your descaling solution
You can use store-bought descaling cleansers or create your own solution using half a cup of white vinegar and half a cup of water.
Fill the water reservoir
Pour the descaling solution into the water tank.
Run a descaling cycle
Place a mug on the drip tray and run a brew cycle without any K cups in the holder. Some Keurig machines have a specific descaling cycle you can run. The cleaning solution will travel through the Keurig machine and dissolve any limescale or mineral buildup in the machine.
Repeat
Repeat the process until all the descaling solution in the water tank has been used, and the scale buildup is removed.
Run two clean water cycles
Now fill the water reservoir with fresh water and run two brew cycles (without a K cup). This brewing process will remove any limescale buildup and cleaning solution still in the pipes. After that, you should be able to brew full cups of coffee.

3. You Have To Unclog The Needle

A Keurig machine has an entrance and exit needle in the brew head. These pierce the top and bottom of the K cup, and the two holes allow hot water to flow in.

The needles can easily become blocked by debris or foil from the K cup lid.

Clogged needles will stop water from flowing through the coffee machine properly and prevent it from making a full cup of coffee.

Thankfully, it's an easy issue to fix, and all you need is a paper clip. Keurig has even made a video to guide you through it.[2]

Remove the pod holder from the brewer
Turn off the machine. Lift the handle, grab the top of the pod holder, and push up from underneath. The pod holder should come right out.
Remove the funnel from the pod holder
Pull on the sides of the bottom part of the pod holder. This gives you access to the exit needle.
Unblock the exit needle
Find the tube on the bottom of the pod holder and insert a paper clip into the exit valve hole. Wiggle it around to remove any coffee grounds or debris.
Wash the pod holder
Rinse the pod holder and funnel under hot water and wash with a small brush to remove any other dirt or debris. When it’s properly cleaned, leave to air dry.
Find the entrance needle
Lift the handle on the coffee maker to open the brew head and locate the entrance needle. There should be two small holes in the needle.
Clean the entrance needle
Take the paper clip and carefully insert it into the holes in the entrance needle. Move it around gently to remove any potential blockages, dirt, or debris.
Reassemble the pod holder
Click the funnel and pod holder back together. Align the pod holder with the arrows in your brew head and slide it back into the Keurig coffee machine.
Run two water-only brews
Run two water cycles without putting a K cup in the holder. This will flush out any dirt you’ve loosened and leave you with unblocked needles.

Other Keurig Brewing-Related Issues & How To Fix Them

Keurig Not Brewing Full Cup After Descaling

Descaling can fix Keurig brewers but can sometimes prevent them from brewing coffee correctly. If you can't get a full cup of coffee after descaling, it's usually one of two things:

1. The Keurig is overheating

Your Keurig can overheat when you make too much coffee, but it can also happen after a descale. Unplug the device and leave it to cool down for 5-10 minutes. Then, test it again to see if it works.

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2. The water filter needs to be replaced

The cleaning solution used during descaling can clog the water filter in your water reservoir. This can disrupt the flow of water.

You can buy a replacement (online is usually easiest) and replace it quickly.

Reach into the water tank, lift the filter out by the filter handle, detach the existing water filter, and attach the new one. Place it back in the tank afterward.

Learn More - Do All Keurigs Have Water Filters?

Keurig Dispensing Too Much Water

This is usually because the water reservoir is too full or placed incorrectly. Here are the troubleshooting steps to go through:

Start by checking the water reservoir positioning. Remove the water reservoir and reattach it securely. Make sure it’s lined up, and rotate it until it clicks into place.
Next, make sure you aren’t overfilling the tank. The amount of water each Keurig can take varies, but there's a water line inside the tank. Don't go over this water level.
Perform a descale cycle. Limescale or dirt on various parts of your Keurig can block the tubing and impact the water pressure. If you notice water leaking, descale the Keurig to get it working properly.

Keurig Will Only Brew Large Cup

This is usually an issue with the system or an electrical component failure. There are a few things you can do to fix it:

Start by checking the Keurig cup size settings, as you may have accidentally set the wrong size. Adjust Keurig cup size and see if that solves the issue.
If not, try resetting your device. Unplug it, wait 30 seconds, then plug it back in. This should reset it to default settings.
If it’s still not brewing correctly, contact Keurig customer service for help.[3]

What’s The Deal With Keurig Cup Sizes?

A Keurig machine will brew a full cup of coffee, but you can usually choose the coffee cup size.

Cup sizes are shown in ounces on most Keurigs, and this is how many ounces of water the Keurig machine dispenses to make one cup of coffee.

The 5 different size options are:

4 ounce
6 ounce
8 ounce
10 ounce
12 ounce

Some Keurigs let you choose from 3 sizes, whereas others (like the Keurig B70) give you 5 options. The Keurig Duo also lets you brew a pot of coffee.

The smaller the size, the more concentrated the coffee. Most K cups are best in 6oz or 8oz sizes and will become weaker and less full-bodied when brewed in larger sizes.

Learn More - Keurig Cup Sizes Explained!

It all comes down to personal preference, but your Keurig should be making coffee in the size you select.

There are a few reasons why it might not be making a full cup, but it’s usually an issue with the Keurig system or a blockage.

Questions About Keurig Not Brewing Correctly

How can you tell if your Keurig is now brewing a full cup?

You can use a measuring cup to see how much coffee your Keurig is brewing. This lets you see if you're getting the right volume when you brew coffee.

How long do Keurigs typically last?

Keurigs usually last 3-5 years if properly maintained.

Will vinegar unclog Keurig?

Yes, descaling regularly with a water and vinegar solution will help to remove limescale or other blockage in the coffee maker and let the water run as it should. It's an important part of keeping your Keurig clean.

How do I make more coffee in my Keurig?

Select a larger cup size to make more coffee in your Keurig. All Keurig models (including Keurig 2.0 models) offer up to 12oz cup sizes, and the Keurig Duo can even make a full coffee pot.

How do you fix a Keurig that won't brew?

If your Keurig machine won't brew, try resetting it. If that fails, contact customer service for expert help.

How to reset Keurig?

You can reset most Keurigs by holding the power button, 8oz, and 10oz buttons for 5 seconds.

To reset the Keurig Classic and Keurig Slim, press and hold the medium, large, and auto-shut-off buttons for 10 seconds.
To set the Keurig Compact, hold the power button, press the smallest button, medium button, and largest button in order.
To reset the Keurig K Supreme, hold down both arrow buttons until you reach the setup menu, click next, then perform a 'Factory Reset.'
To reset the Keurig Mini, turn the machine off and on, leave it for a few minutes, then hold the brew button for 3 seconds.

Conclusion

Keurigs are well-designed, and most issues can be resolved yourself.

If it's not brewing a full cup, it's usually because it's clogged, and a small amount of cleaning and descaling should get it working again.

Hopefully, this guide has explained the most common Keurig coffee maker problems and how to fix the issue with little or no cost.

Remember, proactively cleaning and maintaining your Keurig machine is the best way to keep it running smoothly in the long run.

References:

https://www.dwi.gov.uk/consumers/learn-more-about-your-water/water-hardness-hard-water
https://www.youtube.com/watch?v=g23afr4NijA
https://www.keurig.com/appliances/register-brewer