Water Temperature and Ratio for Filter Coffee: What has changed in 2026

Overview

The new rule of thumb at a glance

In short, this is the consensus that the 2025 and 2026 competitions have revealed:

• Water temperature: 88 to 95 °C, not generally 96 °C. The winner in Brussels brewed at 92 °C.
• Temperature in phases: start hot, finish cooler, instead of a single fixed number.
• Ratio: slightly stronger than before, between 1:13 and 1:15 instead of 1:16 to 1:17.
• Control via extraction: grind size, contact time, and water instead of pure heat.

Important: These are starting points, not rigid rules. If you want to keep it simple, a standard of 90 °C is sufficient, or 88 °C for a slightly brighter, fresher cup. These are also the values on which my recipes in the Recipe Finder are based.

Basics

What water temperature really controls

Temperature is a lever for extraction, i.e., how much from the coffee grounds dissolves into the water. Hotter water dissolves more and faster. This is practical but has two sides.

The soluble substances do not come out simultaneously. First, fruit acids and light aromas dissolve, then sweetness and body, and finally bitter and astringent substances. If you over-extract, you pull out the late, bitter components. If you under-extract, you get stuck in the acidic, thin first phase.

Light roasts are denser and less soluble than dark ones. This led to the old rule "for light, use hot water". It's not wrong, but it's coarse.

Trend

Why "almost boiling" is no longer the answer

The idea of forcing dense light coffees with maximum hot water works, but it sacrifices clarity. In the last two years, the mindset has shifted: instead of pushing the temperature up, the best brewers control resistance and contact time. They grind precisely, reduce fines, choose fast papers and hybrid brewers, and keep the temperature more moderate.

The result is a cleaner, sweeter cup with less astringency. At the World Brewers Cup 2025, winner George Peng from China even made temperature control the centerpiece of his presentation. In 2026 in Brussels, the trend was then visible in the recipes themselves.

Brussels 2026

What the finalists in Brussels brewed

The World Brewers Cup took place from June 25 to 27, 2026, as part of World of Coffee in Brussels. Nas Jaafar from Malaysia won, the first title for his country. Notably, all six finalists brewed a Panama Geisha, mostly naturally processed, and almost all used hybrid brewers with valves.

Two patterns stand out. First, not a single temperature is at the previously common 96 °C. Second, the ratios of 1:13 to 1:15 are noticeably stronger than the classic filter textbook values of 1:16 to 1:17.

Resting time

How old was the coffee? Resting time and degassing

A factor that is easily overlooked: How long after roasting was the coffee? In Brussels, the range was wide. Nas Jaafar roasted three days before the competition, Bavis Kwong six days, Jackie Tran seven, Angie Molina two weeks, Simon Gautherin even rested his coffee for six weeks.

This directly affects temperature and ratio. Freshly roasted coffee contains a lot of CO2. This gas interferes with the contact between water and coffee grounds, slows down extraction, and makes the cup uneven. After one to several weeks of rest, the gas has largely escaped, extraction becomes predictable, and that's when the values in this text apply cleanly.

As a rule of thumb for home: Give light roasts at least about ten days after the roast date, preferably more. I roast weekly in small batches in Berlin and allow each coffee several days of degassing before shipping.

Two temperatures

Temperature in phases instead of a fixed number

The most interesting point: Two finalists, Jackie Tran and Ethan Park, brewed the same coffee with two temperatures within one preparation. Hot water at the beginning, significantly cooler water at the end. In their experience, the hot start opens up aroma and acidity, while the cooler finish slows down the late, bitter extraction. Ethan Park went from 95 °C to 75 °C, Jackie Tran from 94 °C to 80 °C.

At home, the catch is practicality: A single kettle doesn't cool down fast enough to change temperature in the middle of brewing. Heating is fast, cooling is not. So you need the cooler second portion prepared before you start. The easiest way is to pour some hot water into a separate cup and mix in a splash of cold water until you reach around 80 °C. A second kettle makes it more convenient but is not necessary. If you want to save the effort, stick to the simple method with constant temperature; the difference is small.

Ratio

The Ratio: why it can be a bit stronger

A ratio of 1:15 results in a more concentrated cup than 1:17. With modern, very clear coffees like naturally processed Geishas or co-fermented lots, this is desired. These coffees are highly soluble and aromatically dense. A wide ratio dilutes exactly the sweetness and body for which they are purchased.

For everyday use, this doesn't mean that 1:16 is wrong. It means that 1:14 to 1:15 is worth a try, especially for fruit-forward light roasts. Approach it in steps of 0.5 and taste in between.

Adjustments

Resistance instead of heat: grind size, time, and water

Grind size and fines. Grinding finer increases the surface area and thus extraction, even without more heat. The winner in Brussels consciously ground at low speed to produce fewer fines. At home, a good hand grinder helps more than any degree of water temperature.

Contact time and brewer. Hybrid brewers with a valve, such as a Hario Switch, give you control over the contact time. Immersion builds sweetness, percolation at the end ensures a clean finish.

Water. Temperature and ratio only work if the water is right. All finalists used low-mineral water between 35 and 80 ppm. In Berlin, the tap water is too hard and rich in carbonates for this. I have described how to test your values here: The right water for coffee.

Taste

Floral or fruity: what really controls the character

There's a lot of half-knowledge circulating here. The catchy idea "hotter equals fruitier, cooler equals more floral" doesn't stand up to scrutiny. Controlled studies show that water temperature has little effect on taste at the same extraction level and strength. The real lever is extraction, controlled by grind size, ratio, and contact time.

And extraction has a clear direction:

• Under-extracted: sour, sharp, slightly salty, little sweetness, thin body.
• In the ideal range, about 18 to 22 percent: sweetness, balance, and clear, defined fruit.
• Over-extracted: bitter, dry, astringent, hollow.

Here's how to read the graphic: horizontally, the extraction degree; vertically, the intensity. On the left, under-extracted, acidity and fresh, light fruit dominate, but sweetness is lacking. In the middle, in the ideal range, sweetness, balance, and clear fruit are prominent. On the right, over-extracted, bitterness takes over. So "fruity" is not a temperature switch, but a matter of clean extraction.

Where does temperature come into play? It is the tool to hit this ideal range at all, especially with dense light roasts. Too cool, you easily extract too little, and the cup turns sour; warmer, you extract more completely. Hence the corridor of 88 to 94 °C, combined with the appropriate grind size and correct contact time. If you don't want to calculate this combination yourself, you can find it in my Recipe Finder.

Recipe

Your recipe at home, step by step

Here's how to apply this to a light filter coffee, for example an Apricot OD. Two ways, depending on equipment.

The simple way (V60, Origami, any pour-over)

• Ratio: 15 g coffee to 225 g water (1:15)
• Temperature: 90 °C constant, or 88 °C for a brighter, fresher cup
• Grind size: medium, slightly finer than standard
• Bloom: 45 g water, let bloom for 45 seconds
• Then fill to 225 g in two to three pours
• Total time: 2:30 to 3:00 minutes

The Pro Way with Temperature Change (Hario Switch or Brewer with Valve)

Prepare the cooler water for Phase 2 beforehand in a separate cup (hot water plus a splash of cold water, aiming for about 80 °C), because a single kettle doesn't cool down fast enough for this in between.

• Ratio: 15 g coffee to 210 g water (1:14)
• Phase 1: 105 g water at 94 °C, valve open, percolation
• Phase 2: Close valve, 105 g water at 80 °C, about 45 seconds immersion
• Open valve and let drain completely
• Total time: about 2:15 minutes

Taste both against your previous recipe and let the coffee cool slightly for two to three minutes before judging. Light roasts only show their full aroma then.

Assortment

Matching coffees

This technique is particularly worthwhile for light, fruit-forward coffees. Freshly roasted in Berlin.

Apricot OD Peach, white chocolate, vanilla. Light filter coffee from Finca La Sirena, ideal for moderate temperature and strong ratio. 18 € To Apricot OD →

Co-Fermented Trio Apricot OD, Azahar OD and Golden Papayo. Three light filter coffees for experimenting with extraction and ratio. 54 € To Co-Fermented Trio →