The Golden Ratio

Next, we get a bit mathematical here and apply what’s known as the Golden Ratio – this was developed by the Speciality Coffee Association of America (SCAA) to help people know how best to mix coffee and water. It’s generally said to be between 1:15 and 1:18, (coffee : water) which means that for a 150ml cup divided by 18 = 8.3g of coffee per cup. Their official quote puts the same numbers in a different way: “To achieve the Golden Cup Standard, the recommended coffee-to-water ratio is 55 g/L ± 10%”.

Make sure that you always do your conversions to the correct units – it’s probably best to work in grams for everything. It may seem strange to think of grams of water, but it makes the calculations in the Golden Ratio easier to do, as above.

How many coffee beans to use per cup

If you’re wondering how many coffee beans per cup that is in terms of Golden Ration – the answer is roughly 70. It was said that the composer Ludwig van Beethoven used to count out 60 beans per cup for his coffee. But then, again, not all of us have the patience or attention to detail of a genius, so settle for around one and a half tablespoons of grounds per cup.

Table with grams and tablespoons

For ease of reference, here is a handy table with grams and tablespoons showing the amounts of coffee needed to make up to twelve coffees at a time:

Cup of brewed coffee (150ml) Coffee grounds (g) Tablespoons 1 8.3 1.6 2 16.6 3.2 5 41.5 8 6 49.8 9.6 8 66.4 12.8 10 83 16 12 99.6 18.2

So if you want to brew enough coffee or you and your friends, just scale up the ratio calculation we did before.

  • How much coffee for four cups of coffee? Using the Golden Ratio, we know that if one cup takes 8.3g of coffee grounds, then 4 cups would need 33.2g. (The full calculation is that 5fl oz x 4 cups = 20fl oz which equates to 600ml, and 600/18 gives 33g).
  • How much coffee for eight cups of coffee? Well, you’d say that 5fl oz x 8 cups = 40 fl. oz, which is 1200 ml. Using the 1:18 golden ratio (1200 divided by 18), we get 67 grams of coffee for 8 cups, which is just under 13 tablespoons.
  • How much coffee for ten cups of coffee? 5 x 10 = 50 fl. oz 50 fl. oz = 1500 ml. Using the 1:18 golden ratio, that gives us 83 grams of coffee to make our ten cups.
  • What if you want to do coffee for a dinner party and need to know how many scoops for twelve cups? Well, obviously you’ll need to know how much your scoop holds, but it is usually around 5 grams, as we know. Next, do your conversions. 5 fl. oz x 12 = 60 fl. oz equates to 1800 ml. Applying the 1:18 golden ratio, we get 100 grams of coffee for 12 cups.

Additional tips

Let’s look at some additional tips for helping you to get the amounts right, and also to save money. We should mention a bit about grinding here, because the size of ground particles by the type of grinder you use, and that may mean you fit less grounds in your machine. A burr or mill grinder is the best because it produces coffee grounds of a consistent size. (Blade grinders are less good, as they grind the beans nearer the blade for finely than those further away.) Always ‘tamp down’ or push downwards on your grounds once in the machine pod (many machines come with a special tool to do just that).

The different types of coffees you make will each require different grinds – an espresso needs the finest grounds as they are in contact with the water for only around 30 seconds, and so need the greatest surface area contact with the water. The auto-drip machine can take coarser, larger grounds, and the cafeteria requires the coarsest grounds of all.

Nigel Gildon editor:Nigel Gildon is the editor of Chef Wayne’s Big Mamou: Chef Wayne’s Big Mamou. He has worked in the publishing industry for many years and has a passion for helping new authors get their work into the hands of readers. 63 Liberty Street * Springfield, MA 01003

This post was last modified on 12/29/2023 6:06 am