How to Adjust Coffee Taste Using Extraction Rate & Concentration

You’ve brewed a cup of coffee, but something’s off — maybe it tastes weak, sour, or overly bitter. You followed a recipe, but the result just doesn’t hit the mark. How do you know if the issue lies in how much coffee dissolved during brewing — or how strong the cup turned out? That’s where extraction rate and concentration data come in.

The quick answer? For a technically sound cup, aim for a coffee concentration between 1.15% and 1.35%, and an extraction rate of 18% to 22%. These numbers help confirm whether your brewing process is in the right range — even if taste is the ultimate judge.

What Is Coffee Concentration and Why Does TDS Matter?

Coffee concentration refers to how much dissolved coffee material is present in your brewed cup — essentially, how “strong” the coffee is. The standard tool to measure this is TDS, or Total Dissolved Solids. TDS indicates the percentage of the brewed coffee that is made up of actual dissolved coffee solids. The higher the TDS, the more dissolved material is in your cup — and typically, the stronger the flavour.

TDS is measured as a percentage using devices like refractometers. In specialty coffee, the accepted concentration range for a balanced cup is 1.15% to 1.35%. This range helps ensure enough coffee material is present for flavour without being overly intense or weak.

Understanding Coffee Extraction Rate

Extraction rate refers to the portion of soluble material that is successfully drawn out of the coffee grounds during brewing. Not all compounds in coffee are desirable — only a portion contributes positively to taste. According to SCAA (Specialty Coffee Association of America) theory, up to 30% of the coffee's soluble material can be dissolved in water, but not all of it tastes good.

The extraction rate is calculated as:

Extraction Rate (%) = (Mass of extracted coffee solids ÷ Mass of original coffee grounds) × 100

For most brewing methods, an extraction rate between 18% and 22% is considered optimal. Below 18%, the coffee may taste under-extracted — sour, grassy, or weak. Above 22%, it risks becoming over-extracted — bitter, astringent, or harsh. Getting within this window helps balance sweetness, acidity, and bitterness.

How to Use These Numbers to Fix Your Coffee

If your coffee tastes off, checking the TDS and extraction rate can guide your adjustments. Here’s how to think about it:

• If your TDS is low (below 1.15%): The coffee is likely under-concentrated — too watery. Try a finer grind, a slightly longer brew time, or a higher coffee-to-water ratio.
• If your TDS is high (above 1.35%): The coffee is too concentrated — overly strong or intense. Use a coarser grind, reduce brew time, or decrease the coffee dose.
• If your extraction rate is low (below 18%): The coffee is likely under-extracted. Adjust with a finer grind, more agitation, or a longer brew time to pull out more soluble material.
• If your extraction rate is high (above 22%): The coffee is likely over-extracted. Use a coarser grind, reduce contact time, or cool your brew water slightly to slow extraction.

These adjustments help you steer your coffee back toward the ideal balance of strength and extraction — guided by measurable data, not guesswork.

Tools to Measure Coffee TDS and Concentration

One reliable tool for measuring TDS and concentration is the ATAAGO PAL-coffee refractometer. This handheld device is designed specifically for coffee and is both portable and easy to use.

The PAL-coffee model with TDS calibration allows you to quickly measure the concentration of your brewed coffee. It features a simple one-button operation, auto-temperature compensation, and is even water-resistant (IP65 rated), meaning you can rinse it under running water for easy cleaning. Just place a sample on the prism, press a button, and get a reading — no lab needed.

For higher concentration coffee drinks, there’s also the PAL-coffee Brix model, which measures a broader range — 0.00% to 25.00% — making it suitable for extra-strong or concentrated brews. Both tools help ensure consistency and quality control in coffee preparation, especially in shops or for serious home brewers.

Frequently Asked Questions

What is the ideal coffee extraction rate?

The ideal coffee extraction rate is between 18% and 22%. This range ensures that enough soluble material is drawn from the coffee grounds to create a balanced flavour, without extracting overly bitter or astringent compounds. Rates below 18% usually taste under-extracted, while rates above 22% tend to taste over-extracted.

What TDS should my coffee have?

Your coffee should have a TDS (Total Dissolved Solids) between 1.15% and 1.35%. This range represents a well-balanced concentration of dissolved coffee material in the brew, providing enough strength and body for a satisfying cup without being too weak or overly intense.

How do I measure coffee concentration and extraction rate?

You can measure coffee concentration (TDS) and infer extraction rate using a refractometer such as the ATAAGO PAL-coffee. The TDS gives you the percentage of dissolved solids in your brew, and with your brew ratio and coffee dose, you can calculate the extraction rate using the formula: (mass of extracted solids ÷ mass of coffee grounds) × 100.

What happens if my extraction rate is too low?

If your extraction rate is too low (below 18%), your coffee will likely taste sour, weak, or underdeveloped. This means not enough soluble material was extracted from the coffee grounds. To fix this, try a finer grind, increase brew time, or adjust your water temperature upward slightly.

What happens if my TDS is too high?

A TDS above 1.35% means your coffee is too concentrated — it may taste overly strong, bitter, or harsh. To lower TDS, use a coarser grind, reduce your coffee dose, or shorten brew time to allow less coffee material to dissolve in the water.

Are extraction rate and TDS the only factors that affect coffee taste?

No, extraction rate and TDS are important indicators, but not the only factors. Coffee taste is also influenced by roast level, brew method, water quality, grind size, brew temperature, and freshness of the beans. Use TDS and extraction as guides, but always trust your palate as the final judge.

FrontStreet Coffee Beans for Dialling In Extraction

For refining your extraction and concentration control, try FrontStreet Coffee’s Ethiopia Yirgacheffe — bright and floral with citrus and stone fruit, ideal for testing light roast extraction windows. The Colombia Huila Popayan offers balanced caramel and nut notes, great for dialling in medium roasts. For darker profiles, the Indonesia Sumatra Mandheling brings earthy, spicy depth. All three respond clearly to grind and brew adjustments. Freshly roasted within 5 days · Orders placed before 17:00 ship the same day · Next-day delivery across most of Guangdong Province.