TDS (Total Dissolved Solids) is a measurement of all inorganic and organic substances dissolved in water, such as minerals, salts, metals, and organic matter. In brewing, it can be used as a general indicator of mineral content in the water.
What is the role of TDS in your brewing water?
TDS does not directly impact your brewing water, but it can tell you if the water is high in mineral content or not. The way this is typically used is to tell you if your filtration system is effective or not. If you are using a filter like an RO system, your water’s TDS concentration should be very low.
If filtered water has a high TDS, then it’s a sign that your filter needs replaced or repaired. Just because TDS is high doesn’t mean that the water is good or bad to brew with. Just that there is high mineral concentration. What matters more is what those minerals are and if they align with the style of beer you are brewing.
TDS is also useful when buying filtered water to ensure that is has been properly filtered.
TDS amounts in your brewing water
When using TDS to judge the effectiveness of a filtration system, it should be lower than 50 ppm. If it is higher than 50 ppm then you likely need to replace the filter.
Most RO filtered water will be around 20 ppm or less. This shows that it is working properly and gives you a nearly blank slate to build your water profile for brewing beer.
How to measure TDS in brewing water
There are a variety of reliable, inexpensive TDS meters on the market that can be used for brewing water. But TDS only tells you if your water filter is working, not what is in your water. TDS doesn’t tell you what minerals or other matter is in your water.
The Craft Pro Master Brewers Test Kit will let you send a water sample into our EPA Certified Lab and receive TDS concentrations as well as 16 other essential parameters for brewing water such as Chloride, Sulfate, and Calcium.
If you currently use a TDS meter, you can still use it spot check your water quality between In-Lab Testing. If you get In-Lab testing and see that you have a low mineral count and a low TDS, your current TDS meter can be used to compare TDS levels to know there aren’t drastic changes in water quality.
For example, if your Craft Pro In-Lab Test shows you have a TDS of 30 ppm, and then it remains 30 ppm for the following months you know it hasn’t drastically changed. But if your TDS meter now shows 70 ppm, then you have had a major change and need to change your filter and likely get another in-lab test.
Our Craft Pro Test Strips do not measure TDS, but measure several key minerals that can used to tell you if you have had significant changes in water quality like hardness, sulfate, iron, and 6 others.
