Apax Lab TDS Meter
A few drops of water, press a button, wait three seconds – and the display shows a number where there was once a guess. The water that will soon flow through your coffee reveals how much mineral is dissolved in it. "Should be fine" becomes "it is."
What the device measures
Water is never just water, but a solution of H₂O and dissolved minerals such as magnesium, calcium, and bicarbonate. Pure H₂O conducts electricity poorly; the more minerals are dissolved, the more conductive it becomes. The Apax Lab TDS Meter measures precisely this conductivity and converts it into PPM – Parts Per Million, a direct value for how rich in minerals your water is.
Why this matters: With too few minerals, coffee often tastes flat because the water lacks the partners to dissolve and carry aromas. With too many minerals, the mineral impression can overpower the delicate notes. In between lies the range where body and clarity come together. Where exactly your optimum lies is also a matter of taste – our observation is one of many.
At a glance
| Brand |
Apax Lab |
| Measurement |
Mineral content of water (TDS) in PPM |
| Measuring Range |
0–9990 PPM |
| Accuracy |
±2% |
| Probe |
Titanium |
| Functions |
Auto-Off, Hold, Temperature Compensation |
| Display |
LCD |
| Protection |
waterproof (IP67) |
| Battery |
included, replaceable |
| Calibration |
pre-calibrated, ready to use |
How to proceed
First, check the base water: distilled or osmosis water should be close to 0 PPM – the clean starting point. Then, mix your water according to the recipe, immerse the probe, press the button, and read the value. If it matches your goal, brew with the certainty that the foundation is sound. If it's off, correct it next time – and because the result is a number, it can be precisely replicated the next day.
With the TDS Meter, you can check Apax Lab water recipes like Tonik, Jamm, or Lylac. As an importer of Apax Lab in Switzerland, we supply it with original products and support.
Who it's for
For everyone who wants to see, not guess, their brewing water – whether you work with Apax Lab profiles, seek consistent results day after day, or simply want to understand what's happening in your cup. And for anyone whose tap water fluctuates seasonally and wants quick certainty before brewing.
The right setup
Water and scales go hand in hand: For precise dosing, you'll find affordable, reliable models in our Normcore Collection, and if you want app, flow rate, and Bluetooth, check out the Acaia Collection. If it's about water for a plumbed-in machine, it's worth looking at the filter solutions in our Brita Collection. More about brewing can be found in the Barista Tools.
Frequently Asked Questions
Does the TDS Meter also measure the espresso in the cup?
No. It measures the minerals dissolved in the water, i.e., the TDS of the brewing water. For the dissolved coffee solids in finished espresso, a refractometer is needed – it works with light refraction and is a different tool.
What PPM value is suitable for coffee?
The pleasant range is often between 80 and 120 PPM, tending to be slightly higher for espresso and slightly lower for filter coffee. This is a guideline and a matter of taste – our recommendation is one of many.
Do I need to calibrate the device?
It comes pre-calibrated and ready to use. After prolonged use, it can be readjusted with a calibration solution; for most, this is rarely necessary.
Can I see the TDS Meter before buying it in person?
Yes, in our showrooms in Bern and Zurich. Delivery within 2 to 4 working days throughout Switzerland and Liechtenstein.
As a coffee roastery, we see water as part of the recipe, not an afterthought – it makes up over 90% of the beverage. Those who measure the basic water once and then brew a full-bodied roast like Cozy Chocolate or Nutty Delight often taste the difference more clearly. This is our recommendation, one of many.
