Apax Lab TDS Meter
A few drops in the water, a press of the button, three seconds of waiting – and the display shows a number where there used to be a guess. The water that's about to run through your coffee reveals exactly how much mineral is dissolved in it. «Should be about right» becomes «this is it».
What the device measures
Water is never just water – it's a solution of H₂O and dissolved minerals like magnesium, calcium, and bicarbonate. Pure H₂O barely conducts electricity; the more minerals are dissolved in it, the more conductive it becomes. The Apax Lab TDS Meter measures exactly this conductivity and converts it into PPM – parts per million, a direct value for how mineral-rich your water is.
Why it matters: with too little mineral content, coffee often tastes flat, because the water lacks the partners needed to dissolve and carry aroma. With too much mineral content, that mineral impression sits on top of the finer 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 you do it
Start by checking your base water: distilled or reverse-osmosis water should read close to 0 PPM – the clean starting point. Then mix your water according to a recipe, dip in the probe, press the button, and read the value. If it matches your target, you brew with the certainty that the foundation is right. If it's off, you adjust it next time – and because the result is a number, it repeats exactly the next day.
With the TDS Meter you check the Apax-Lab water recipes like Tonik, Jamm, or Lylac. As the importer of Apax Lab in Switzerland, we supply it with original goods and support.
Who it's for
For anyone who wants to see their brew water rather than guess at it – whether you work with Apax-Lab profiles, look for consistent results day after day, or simply want to understand what's happening in your cup. And for anyone whose tap water shifts with the seasons and who wants quick certainty before brewing.
The right setup
Water and scale go together: for precise dosing you'll find affordable, reliable models in our Normcore Collection, and if you want app control, flow-rate display, and Bluetooth, take a look at the Acaia Collection. When it comes to the water for a plumbed-in machine, it's worth a look at the filter solutions in our Brita Collection. More on brewing and preparation 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 – the TDS of your brew water. For the dissolved coffee solids in the finished espresso, you need a refractometer – that works with light refraction and is a different tool.
Which PPM value is suitable for coffee?
The pleasant range is often between 80 and 120 PPM, tending a bit higher for espresso and a bit lower for filter. That's a guideline and a matter of taste at the same time – our recommendation is one of many.
Do I need to calibrate the device?
It arrives pre-calibrated and ready to use. After extended use, it can be readjusted with a calibration solution; for most people, that's rarely necessary.
Can I see the TDS Meter in person before buying?
Yes, in our showrooms in Bern and Zürich. Delivery takes 2 to 4 business days throughout Switzerland and to Liechtenstein.
As a coffee roastery, we see water as part of the recipe, not an afterthought – it makes up over 90% of the drink. Measure that foundation once, then brew a full-bodied roast like Cozy Chocolate or Nutty Delight and you'll often taste the difference more clearly. That's our recommendation, one of many.
