TDS and Coffee: Understanding Dissolved Solids for Perfect Coffee at Home

What is TDS?

TDS measures the proportion of dissolved solids in your coffee, expressed as a percentage (%). These particles include oils, sugars, acids and soluble compounds extracted from the ground coffee during brewing.

Typical TDS for different preparations :

• Filter coffee : Between 1.15% and 1.45for a balanced, smooth coffee.
• Espresso : Between 8% and 12more concentrated and intense.
• Cold brew : About 1,2 % à 1,4 %but with a texture that is often rounder and softer.

These figures do not determine taste per se, but they do indicate whether your coffee is properly extracted.

Why is TDS important?

TDS is essential to understand whether your coffee is sub-extract, well extracted or over-extracted :

• Under-extraction TDS too low. Aromas remain locked in the ground coffee, making your cup bland or acidic.
• Good extraction Balanced TDS. Flavors are harmonious, natural sugars are present, and acidity is pleasant.
• Over-extraction TDS too high. Coffee is bitter and loses its delicate notes.

The TDS is therefore a analysis toolThis allows you to adjust your settings for ideal extraction and a perfectly balanced cup.

Factors influencing TDS

TDS is influenced by several variables in the extraction process. Here are the key elements to monitor:

1. The Coffee/Water Ratio

The ratio determines the concentration of your coffee. For example:

• A ratio 1:2 (1 g coffee to 2 g water) is typical for an espresso.
• A ratio 1:15 à 1:18 is ideal for filter coffee.

2. Water temperature

Hot water extracts coffee compounds more quickly. The ideal range is 90 to 96°C. Water that is too hot may over-extract aromas, while water that is too cold may limit extraction.

3. Grinding

Grind size affects the contact surface between water and coffee:

• Too fine a grind Extraction too rapid, leading to bitter or unbalanced notes.
• Too coarse a grind Under-extraction, resulting in bland or acidic coffee.

4. Extraction time

The right infusion time is essential:

• For an espresso, extraction generally takes between 25 and 30 seconds.
• For filter coffee, the water should brew between 3 and 4 minutes.

5. Water Quality

Water with the right mineral balance is essential. Water too rich in minerals can interfere with flavors, while water too soft could prevent full extraction. Opt for filtered water with a TDS between 50 and 150 ppm.

How to use TDS at home

Although you don't need to measure TDS for every cup, knowing this concept can help you understand what influences the taste of your coffee. Here are some practical tips:

• Start with proven recipes Use a coffee/water ratio suited to your brewing method.
• Add progressive adjustments Change one variable at a time (grind, temperature or time) to observe its impact on taste.
• Invest in a refractometer For the discerning enthusiast, this can be a fun tool for exploring the nuances of extraction.