Why Ratio Matters in Filter Coffee

The Moccamaster is one of the simplest and most reliable ways to brew filter coffee at home. Furthermore, because the machine handles temperature and water flow automatically, the variables you can control come down to a few key choices: the coffee, the grind, and the ratio.

Of these, the ratio of coffee to water has the biggest single impact on how the cup tastes. As a result, getting the ratio right is the foundation of brewing a consistently great Moccamaster. To understand how brewing fits into the bigger picture of coffee flavour, read our pillar guide on how to brew better coffee at home.

The Recommended Moccamaster Ratio: 1:15

At Routes, we recommend a 1:15 coffee-to-water ratio for most specialty coffees in a Moccamaster. In other words, 67g of coffee per litre of water. To calculate the dose for any volume, divide the millilitres of water by 15:

• 1 litre (1000ml) water needs 67g coffee
• 500ml water needs 33g coffee
• 250ml water needs 17g coffee

Furthermore, the 1:15 ratio strikes a good balance between strength and clarity. As a result, it works well across most origins and roast styles.

Why 1:15 Works for Specialty Coffee

Different ratios produce different cups. Moreover, choosing the right one depends on the coffee you’re brewing and how you like your filter:

• 1:14 (stronger). Produces a fuller-bodied, more intense cup. Furthermore, this ratio brings out richness, but can also amplify bitterness if anything else is off.
• 1:15 (balanced). The Routes default. Balanced flavour, body, and clarity. Works for most specialty coffees.
• 1:16 (lighter). A milder, cleaner cup. As a result, this ratio is great for delicate, fruit-forward coffees where you want clarity to dominate.
• 1:17 to 1:18 (very light). Industry standard for some specialty coffees. Produces a tea-like, transparent cup. On the other hand, this can taste thin if the coffee or grind isn’t dialled in.

If you’re not sure where to start, 1:15 is the safest bet. Consequently, you can always adjust based on what you taste in the cup.

The Right Grind for a Moccamaster

Grind size is the second most important variable. Because the Moccamaster brews automatically and quickly, the grind needs to match the brew time the machine sets:

• Texture: medium-coarse, similar to coarse sea salt or rough sand.
• Microns: roughly 500 to 800 microns if your grinder shows numbers.
• Common grinder settings: usually around the middle to upper-middle of most home burr grinders.

Furthermore, freshness matters. Always grind just before brewing for the best results. As a result, your Moccamaster delivers cups that taste close to what professional baristas produce.

Water Quality and Your Moccamaster

Water is around 98 percent of the final cup, so its quality directly affects how your Moccamaster coffee tastes. Furthermore, hard water also causes limescale buildup inside the machine, which can damage the boiler and dull flavour over time. Consequently, using filtered or soft mineral water is one of the most overlooked upgrades for filter coffee.

Avoid distilled or reverse osmosis water on its own. Moreover, this can damage the Moccamaster’s copper boiling element and produces flat, sour coffee. For more, read our guides on water quality in coffee brewing and limescale: the silent flavour changer.

The Moccamaster Method, Step by Step

Brewing a 1-litre batch in a Moccamaster takes about 5 to 6 minutes. Furthermore, the steps are straightforward:

1. Weigh and grind the coffee. Measure 67g of coffee on a scale, then grind to coarse sea salt texture.
2. Prepare the filter. Place a paper filter in the brew basket and rinse with hot water to remove papery residue. Discard the rinse water.
3. Add the water. Pour 1 litre of cold filtered water into the Moccamaster reservoir.
4. Add the coffee. Tip the ground coffee into the rinsed filter and gently shake to level the bed.
5. Brew. Turn the machine on and let it complete its full cycle. Furthermore, the Moccamaster’s shower head produces a 30-second bloom before the main brew, which is critical for even extraction.
6. Swirl and serve. Once finished, swirl the carafe gently to mix the brew before pouring. As a result, you get a balanced cup from first sip to last.

Adjusting Your Moccamaster Brew

If your cup doesn’t taste right, the fix is usually small. Moreover, here are the most common problems and how to solve them:

• Too bitter. Grind coarser, increase the ratio (try 1:16), or check for limescale. Furthermore, if you’re using a dark roast, switching to a medium roast can help. For more, read our guide on why coffee tastes bitter.
• Too sour or weak. Grind finer, decrease the ratio (try 1:14), or use fresher coffee. Furthermore, see our guide on why coffee tastes sour.
• Tastes flat. Check freshness and water. Stale beans or hard water often produce dull cups.
• Uneven extraction. Make sure the coffee bed is level after adding grounds. Moreover, swirl gently after brewing to mix the carafe.

Which Coffees Work Best in a Moccamaster?

Almost any specialty coffee works well in a Moccamaster. However, certain styles particularly shine in this brew method:

• Washed coffees. Clean and structured, these highlight the Moccamaster’s strengths in clarity. Moreover, our Rwanda: Bourbon (Washed) works beautifully.
• Naturals. Fruit-forward and sweet, these produce dessert-like filter coffees. Furthermore, our Ecuador: Mitad del Mundo (Natural) is a great choice.
• Honey and anaerobic processed. Sweet, complex, and aromatic. As a result, they produce filter coffees with real depth.
• Medium roasts. The Moccamaster’s brewing temperature is well-suited to medium-roasted specialty coffees. On the other hand, very dark roasts can become overly bitter in this brewer.

To understand more about how processing affects the cup, read our complete guide to coffee processing methods.

Brewing Better Filter Coffee with Routes

The Moccamaster is at its best with freshly roasted specialty coffee. Furthermore, a Routes Coffee subscription delivers freshly roasted single origins and blends to your door, so you always have great beans ready for your next brew. As a result, every batch you make is starting from the best possible base.

Frequently Asked Questions

What is the best Moccamaster coffee ratio?

The best Moccamaster ratio for most specialty coffees is 1:15, which means 67g of coffee per litre of water. Furthermore, this ratio produces a balanced, full-flavoured cup. Adjust to 1:16 or 1:17 for a lighter cup, or 1:14 for something stronger.

How much coffee do I use for one litre in a Moccamaster?

Use 67g of coffee for 1 litre of water at a 1:15 ratio. To calculate any ratio quickly, divide the volume in millilitres by the second number in the ratio. For example, 1000 divided by 15 equals 67g.

What grind size should I use for a Moccamaster?

Use a medium-coarse grind, similar in texture to coarse sea salt. Furthermore, if your coffee tastes bitter, grind slightly coarser. If it tastes sour or weak, grind slightly finer.

Why does my Moccamaster coffee taste bitter?

Bitter Moccamaster coffee is usually caused by too fine a grind, too high a coffee dose, dark roasted beans, or limescale buildup in the machine. As a result, try a coarser grind, a higher ratio (e.g. 1:16), a lighter roast, or descale the machine.

Why does my Moccamaster coffee taste weak?

Weak Moccamaster coffee is usually caused by too coarse a grind, too little coffee, or stale beans. Furthermore, try a slightly finer grind, increase your dose to a 1:14 ratio, or use freshly roasted coffee.

How often should I descale my Moccamaster?

Descale your Moccamaster every 3 months if you live in a hard water area. Moreover, regular descaling preserves both the machine and the flavour of your coffee. Use a descaling product designed for coffee machines, not vinegar.

Can I use the Moccamaster for cold brew?

No. The Moccamaster is designed for hot filter brewing. For cold brew, use the steeping method instead. Read our guide on how to make cold brew coffee.

Related Reading

• Routes Coffee, How to Brew Better Coffee at Home (pillar)
• Routes Coffee, Why Water Quality Is Important in Coffee Brewing
• Routes Coffee, Limescale: The Silent Flavour Changer in Your Coffee
• Routes Coffee, How to Make Cold Brew Coffee
• Routes Coffee, Why Does Coffee Taste Bitter?
• Routes Coffee, Why Does Coffee Taste Sour?

Sources & Further Reading

• Specialty Coffee Association, brewing guidelines and golden cup standard.
• Moccamaster, official brewing recommendations.
• Rivera, J. A. Roast Magazine, filter brewing extraction science.