How to Avoid Leaking

Nobody wants to arrive at work with coffee stained clothes. The Oomph is designed so you can take an amazing cup of coffee with you anywhere, so, although a  rare occurrence, a leaky Oomph in the morning is far from ideal. If you are experiencing problems with a leaking then don’t worry. Here are a few quick and easy troubleshooting tips that could save your morning – and your favourite shirt!

Don’t turn it upside down!

It may sound obvious but we need to get this out of the way. The Oomph’s lid is not designed to be completely water tight! Although a leak proof lid is currently in development, like many portable hot drinks vessels, the Oomph’s current lid is built for convenience and functions primarily as an easy flow drinking solution, not a complete water tight seal. So whilst you will be able to drink from it comfortably, we don’t recommend throwing a full Oomph into your gym bag just yet.


Tighten it up!

When in use, the seal around the underside of the lid should always be in tight contact with the main section of the Oomph’s body. The smallest gap will allow precious coffee to leak out! To stop this make sure the lid’s screw in threads are correctly located. Begin by ensuring the lid is completely parallel with the screw in section and turn clockwise gently. If the lid tilts or you begin to encounter resistance, remove and start again. Once you are certain there is no cross threading, give the lid one last strong twist to tighten.


Hint: The flip over drinking hole cover will clip into place if flipped completely. This will give you a handy lever grip to ensure the lid is on as tightly as possible.

Those all important seals. 

Before you begin to brew on the Oomph it is always good to check your seals are properly located. We’ll deal with checking the ‘D’ seal below. If you are sure your ‘D’ seal is seated correctly, however, there is another seal underneath which could cause potential leaking issues. We’ll call this the ‘L’ seal as when it is located properly it should form an inverted ‘L’ shape as opposed to sitting flat (see image below). The purpose of this seal is to form a waterproof barrier between the inner and outer chambers. The key time to check that the ‘L’ seal has not flipped out of place and lost it’s all important ‘L’ shape is any time you have had the inner and outer chambers separated for cleaning. Before you screw the chambers together just be sure to look for the ‘L’!


An initial step towards solving the problem of a difficult-to-plunge Oomph (especially if the Oomph has previously been working fine) is to thoroughly clean the filter. Microscopic coffee grounds can begin to clog the Oomph’s stainless steel filter over time making it difficult to force liquid through. Therefore we recommend that you soak the filter in bicarbonate of soda and water or lemon juice overnight at least once a month. This will keep the filter clean and functional and reusable for a long time!


The seal in question is known as the ‘D’ seal as it is shaped just like a capital letter ‘D’.   As you will see from the illustrations, it is important that the flat edge of the D is placed into the groove around the top of the Oomph first, with the rounded edge exposed. If the rounded edge is sat in the groove then a proper seal cannot be formed and liquid will escape. Moreover, the extra protrusion of the gasket will prevent the lid and external cover from fitting properly, making plunging and locking the Oomph difficult or impossible.


Fixing the problem is easy:

  • Firstly, remove the ‘D seal’ completely, being careful not to stretch or tear the rubber.
  • Check that the rounded edge of the D is to the top.
  • Begin gently pressing the flat edge into the groove.
  • To ensure it is fully located, turn the device upside down and press against a flat surface.
  • Check the seal is fully located and there are no gaps or bumps in the gasket.
  • Test the Oomph by brewing a fresh coffee.






Once the ‘D seal’ gasket is fully in place, the outer casing should fit properly and lock into place and the Oomph should not leak during drinking or pouring – but remember, the lid is NOT designed to be water tight and WILL therefore leak if turned upside down or left on its side. A water tight lid is currently in development and will be in production soon.

From plunging to clicking into place, once the Oomph has been used a few times it will begin to feel easier and more responsive to make coffee with. Because the Oomph is designed to withstand use for thousands of brews, it is made of robust, durable materials which can feel a little resistant at first.

If you are finding it difficult to lock your Oomph into place, here’s a little workaround which should ‘train’ your device to close and lock much easier.

    • Disassemble the Oomph by removing the lid and outer casing.
    • Unscrew the inner chamber and separate.
    • Place the lid and inner chamber to one side and, taking just the outer casing and the base, slide together as if plunging and lock the hooks into place.
    • Unlock and click back into place around ten times.
    • Rotate the outer casing so that the next hook is placed in the next locking position. Repeat the above step.
    • Rotate once more and repeat until each locking hook has been worn into each cavity around ten times.
    • Completely reassemble your Oomph and prepare a coffee as normal .You should find both the plunging and locking operations much easier.
If you are continuing to experience problems please email us and we will do whatever we can to help.
The Oomph Team