Tool
Stronger, weaker or better brew assistant
Two separate questions kept separate: make it stronger or weaker, which is a ratio change, and make it taste better, which usually is not.
New ratio
1:14.5
From 1:16.7. There are two ways to get there, and they produce different amounts of drink.
Change the coffee
34 g coffee · 500 g water
Same amount of drink, more or less coffee in it.
Change the water
30 g coffee · 435 g water
Same coffee, a different amount of drink.
Keep the grind exactly where it is. This changes how much coffee is in the cup, not how far it extracted — and moving both at once means the result explains nothing.
How this was worked out
Current ratio = water ÷ coffee
500 ÷ 30 = 1:16.7
New ratio = current ratio ÷ (1 + 15%)
16.7 ÷ 1.15 = 1:14.5
The step is applied to coffee per water, so a stronger brew always gives a smaller second number.
Exact arithmetic on your numbers
How it works
Strength and extraction are different axes and confusing them is why so much brewing advice contradicts itself. If you want a stronger or weaker drink, the tool adjusts the ratio and shows the new numbers. If the brew tastes sour, bitter, thin or harsh, it treats that as an extraction problem and ranks the levers — grind first for most methods, then contact time and agitation — with what to leave alone while you test.
What the inputs mean
- Concentration
- How much dissolved coffee is in the cup. Adding more coffee at the same grind makes a stronger drink without extracting each particle any further.
- Extraction
- How much of each coffee particle has dissolved. Grinding finer, brewing longer or agitating more all extract further, which changes the taste rather than only the strength.
- Brew time
- From the first water to the last drip. For immersion it is the steep; for pour-over it includes the drawdown.
Worked examples
A V60 that tastes fine but weak
- 30 g coffee, 500 g water
- Make it stronger
Result: About 34.5 g of coffee at the same 500 g of water, which is 1:14.5 rather than 1:16.7. Keep the grind where it is.
A French press that tastes bitter and drying
- Immersion
- Bitter and drying
Result: Grind coarser first, then shorten the steep. Leave the ratio alone until it stops tasting bitter.
Common mistakes
Brewing longer instead of adding more coffee
A longer brew extracts each particle further, which changes the flavour balance and eventually adds bitterness. It is not a way to add strength.
Adding more coffee to fix sourness
Sourness is under-extraction. More coffee at the same grind gives a stronger sour drink.
Changing grind and ratio at once
The two move different things and the result cannot be attributed to either.
What the result does not mean
- Stronger does not mean better extracted, and better extracted does not mean stronger. The tool keeps them apart on purpose.
- Ranked guidance, not a diagnosis. Where a symptom has several plausible causes the tool lists them in order rather than choosing.
What this does not account for
- Strength steps are proportional adjustments to the ratio, not evidence-derived thresholds. A 'slightly stronger' step is about 8%, and a 'stronger' step about 15%.
- Grind step sizes are described relatively, because grinder numbering is not comparable between machines.
- Assumes the coffee is reasonably fresh. Stale coffee tastes flat regardless of what you adjust.