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Coffee Brewing Ratios Explained by James Hoffmann

I. Why Grams per Litre is the Best Ratio​

Hoffmann recommends using a ratio based on weight (grams) instead of volume (scoops or cups) because:

  • Inconsistency of Volume: Volumetric measurements (scoops, tablespoons) lead to massive weight fluctuations. A dark roast, medium-ground coffee might weigh 7.5 grams per scoop, while a light roast, finer-ground coffee could weigh 8.5 grams (over 10% more). This inconsistency means your coffee will taste great some days and bad on others, even if you "did the same thing".
  • Easy Math: Ratios like 1:15 are confusing for working backwards. If you want to brew 500ml of coffee, it's easier to use grams per litre: if the ratio is 60 grams per litre, you need 30 grams for half a litre.
  • Scalability: The grams-per-litre ratio scales easily whether you are brewing one 250ml cup or a full litre.

II. Finding Your Ideal Ratio (Strength vs. Extraction)​

Hoffmann clarifies that the ideal ratio is a matter of personal preference for strength, but it should only be adjusted after achieving optimal extraction (taste).

1. The Starting Point​

  • Hoffmann recommends 60 grams per litre (60g/L) as a good, one-size-fits-all starting point that satisfies most people.
  • The ratio you use ultimately determines the strength of the final cup.

2. Extraction vs. Strength​

  • Extraction refers to the percentage of soluble material dissolved from the coffee grounds (ideally around 20% of the mass). Good extraction creates a delicious cup; poor extraction results in sourness, hollowness, or bitterness.
  • Crucial Rule: If you brew a cup that tastes delicious but you wish it was stronger, that is the time to change your ratio (e.g., go from 60g/L to 65g/L).
  • Mistake: If the coffee is weak, sour, or not delicious, do not change the ratio. Instead, improve the extraction by grinding a little finer, steeping a little longer, or increasing agitation.

III. Ratio Adjustments for Different Brewing Methods​

Hoffmann divides all brewing into two camps and recommends different starting ratios for each, based on how much water is retained by the grounds:

1. Percolation (Pour-over, Drip)​

  • Definition: Water passes through a bed of coffee (e.g., V60, Chemex, Drip machine).
  • Water Loss: In this method, the coffee grounds absorb about 2 grams of water per gram of coffee. This absorbed water (which typically amounts to 10–12% of the total water) does not end up in the final cup, making the resulting brew slightly stronger.
  • Recommended Ratio: ~60 grams per litre.

2. Infusion (Immersion)​

  • Definition: All of the water and all of the coffee grounds hang out together during the brew time (e.g., French Press, AeroPress, Cupping).
  • Water Use: All the water is fully involved in the brewing process. If you use 1,000 grams of water, the dissolved coffee is distributed across all 1,000 grams. This means that for the same amount of coffee extracted, the resulting cup is slightly weaker than a percolation brew.
  • Recommended Ratio: ~75 grams per litre.