Keurig K-supreme descale light stays on after descaling? [Fixed]

Here are the best fixes if your Keurig K-supreme descale light stays on even after the descaling is completed.

To turn the descale mode ON in the Keurig K-supreme model, hold the 8oz and 12oz together instead of the 8oz and 10oz buttons. Secondly, the wrong usage of vinegar and citric acid as descaling agents can affect your machine in the long run and are unsuitable for espresso descaling.

I spent a whole day researching all possible problems and the best fix for Keurig K-supreme, K-supreme Plus, and the latest K-supreme smart espresso machine in particular.

The official Keurig K-supreme guide is incomplete and most of the solution for this problem is very generic and incomplete.

A scale that is only 3/16” thick will cause the machine to use 27% more water/energy and cause your coffee to taste poor. Consider using filtered water and not water directly from the tap for a longer machine life.

Read also: Keurig K350 vs K450 – The best everyday coffee maker

How to descale Keurig K-Supreme models properly?

In the Keurig k-supreme models, like K-supreme, K-supreme Plus, K-supreme smart, descale light blinks but never turns off even after multiple descaling attempts. This is an annoying problem and is not covered well in the K-supreme user guide properly.

The following are the common reasons if you are struggling to turn that ‘Descale’ light off.

1. You are not doing the descaling process properly. As a rule of thumb, descaling in K-supreme models run for 2 cycles of running through the water tank, one with the descaling agent and the other with plain water
2. You are using a milder descaling agent, like citric acid. This will require multiple descaling attempts to clean the inner pipes from the carbonate deposits.
3. Ensure that the water reservoir is clicked in place. Place it in position and press it till you hear the click sound.
4. Did not clean the K-cup holder and the needle which might also have scales on them.

During descaling, the k-supreme models have been (poorly) programmed to follow the below steps only.

1. Unplug your machine
2. With the power button not lit, press and hold the 8oz and 12oz buttons. This is different from the previous models where 8oz and 10oz trigger the descaling process.
3. Descale light should go from blinking to solid ON
4. Fill the tank with the descaling agent of your choice.
5. Press the brew button and wait for the descaling fluid to drip completely.
6. If the brew button stops but the tank is not yet empty, press it again to let the remaining fluid through. Remember to not use more than 8oz of descaling fluid for the first time.
7. Important: Once the reservoir is empty, remove the tank to clean it and fill it with water. Not removing the reservoir might still cause your descaling light to be on after you are done.
8. Press brew to let the water drip. Repeat until the water tank is fully empty.
9. Descale light should be out by this time. If it still doesn’t turn off, consider using a rinse pod to clean up the scales in your K-cup holder and needle
10. Press the power button and wait for the unit to turn on normally.

People often mistake step 2 and step 7 and end up performing normal brewing without entering into descale mode.

Unclean water tank filter causes descale light to stay on

The water tank filter for K-supreme variants is good but not the best. They can handle debris and other contaminants that are considerably bigger but often lets the smaller contaminants through.

To clean the water tank filter, empty the tank and remove the filter in the center by pressing to pop it out. If the water tank has not been cleaned for a long period, the filter might be stuck tightly.

Clean the filter normally with running water, or gently rub with a tooth-brush to remove the debris. Do not use any chemical or washing solution here as the micro filters will retain some of the chemical and seep it into the water tank.

Machine turns off after descale is complete

This is normal, and the machine will continue to work after you turn it on

The main issue is that people forget to remove the water tank holder after the first cycle of the descaling fluid. Remove the water tank to refill, and do not pour the water into the tank directly. This seems to be a poor engineering design from the Keurig k-supreme models.

You wouldn’t have entered descale model at all. If the descale light does not blink, you are just brewing normally. This can happen because keuring k-supreme plus and k-supreme variants allow you to brew but k-supreme smart does not perform brewing unless the descale procedure is completed

Pod cupholder is not clean

The pod cupholder or K-cup holder would have to be descaled as well. The needle that punctures the pod might have also developed scales.

You can fix this by manually cleaning the pod holder and the needle that punctures the pod. Use a damp cloth and citric acid solution to gently clean it.

However, most of these scales are difficult to remove and not reachable by hand. A good way to clean the pod cupholder is to use a rinse pod, that is available with the Keurig cleaning kit (recommended) after your descaling is complete.

1. Put the rinse pod normally like your brew pod
2. Perform normal brewing by closing the lid and pressing the 8oz button
3. Place a cup in the drip tray to collect the dirty water
4. Be safe around the cup and drip tray as the rinse pod contains baking powder that will release a lot of carbon dioxide when dripping

Machine is dead because of overdoing cleaning and rinsing cycle

Overdoing the cleaning and rinsing cycle (descaling) can cause the thermostat inside to overheat.

If the thermostat is fried, the machine is of no use anymore. However, there is a paper clip technique that will be useful to reset the dead Keurig K-supreme if the thermostat has gotten reset.

How to reset a dead Keurig K-Supreme?

We do not recommend opening the unit to fix the machine as this may nullify your warranty.

It is easier to get customer support to offer a replacement instead of trying to fix it yourself because doing the reset wrongly might damage the inner circuit

But for those who are desperate and need a quick fix, do the following

1. Open the bottom half by pushing the corners to release the unit holding. Use a flat screwdriver if you cannot do it by hand
2. Slowly remove the outer cover of the unit but keep in mind that it will not come out immediately. You might have to adjust the K-cup lid and the button panel to wiggle the outer layer out
3. Locate the thermostat, in the middle, which looks like a rod wrapped with a coil around it
4. Now find the electrical unit connected to the top of the thermostat. You will find a circular fixture that is responsible for acting as the resistor
5. Take a small paper clip, and press the hole in this circular unit
6. If you cannot find the hole, put the machine horizontally on the table and look for the circular unit closer to the button panel.

If none of this works out, it is better to reach out to Keurig support and get your machine replaced

Bad descaling agents might cause permanent damage

Firstly, nothing against citric acid solutions, but they are mild acids that cannot be very suitable for coffee machines.

Weaker acid takes multiple descaling cycles to remove the scale deposits. This can be the main reason why your Keurig coffee maker might have the descale light staying on.

I personally do not prefer vinegar as a descaling agent, it is corrosive towards some metals, especially brass. Using vinegar for an extended period can cause the brass to turn into lead which can seep into your coffee. Yuck! Don’t use that.

A good recommended descaling agent has inhibited or “buffered” acids that inhibit the corrosive effect of the acids on various materials.

The scale often contains silica and other contaminants, which also need to be accounted for when performing descaling. Use the recommended descaling agent, preferably a 8Oz bottle to perform periodic descaling for the extended life of your machine.

When to reach out to customer care?

Firstly, you can reach out to customer care at 866-901-2739. Before you reach out to Keurig customer care, register your brewer by entering your serial number.

You can find the serial number for your K-supreme variants on the bottom of the brewer. Remove the water tray and flip the brewer to find it.

The normal warranty period is 1 year for all Keurig models, but they usually accommodate defective models if that is diagnosed as the problem.

In the end, if none of this works out, consider replacing your machine. The Nespresso Vertuo line of coffee maker is very good in quality that will stay with you for a long time.