September 25, 2025
Swirl, stir, or leave the bloom: Has specialty coffee decided what’s best?
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- The bloom is a crucial step in the filter coffee brewing process. One of the most common ratios for blooming is a 2:1 water-to-coffee ratio; however, some baristas and competitors use more water for pre-infusion, ranging between 3:1 and 4:1.
- As water comes into contact with the ground coffee, it releases carbon dioxide and oils, indicating freshness and facilitating even extraction.
- Swirling or stirring can aid the bloom, increasing extraction levels, but excessive agitation can cause fine coffee particles to clog the flow of water.
- These practices vary from café to café, raising the question of which one works best – but it’s dependent on a number of factors, especially yield and batch size.
- More national and World Brewers Cup Championship competitors are moving away from the idea of the bloom altogether, instead focusing on multiple smaller pours.
Blooming (or pre-infusing) filter coffee is an essential part of the brewing process: it’s when water first comes into contact with the coffee grounds. Many baristas use water-to-coffee ratios of 2:1 to 4:1 to allow enough carbon dioxide to be released from the grounds.
However, there’s little agreement on what should happen next. Some consider agitation to be a crucial step when preparing pour over or filter coffee. Stirring or swirling the slurry (the mixture of ground coffee and water) can improve the distribution of water throughout the coffee bed, minimising channeling.
Others, meanwhile, leave the slurry, providing no agitation and instead focusing on multiple smaller pours – effectively reimagining the concept of the bloom altogether.
So, is there a “right” way to bloom coffee – or are there too many factors at play to decide? Nicole Battefeld-Montgomery, German Brewers Cup, Barista, and Coffee in Good Spirits Champion, shares her insight.
You may also like our article on how agitation affects filter coffee brewing.
Why do we agitate the coffee bloom?
The importance of the bloom when preparing filter coffee cannot be overlooked. Not only does it pre-infuse water into the dry coffee grounds, effectively preparing them for a more even extraction, but it is also an indicator of a coffee’s freshness.
When ground coffee comes into contact with water, it releases carbon dioxide, which appears as bubbles on the surface of the slurry. The fresher the coffee is, the more carbon dioxide it contains – therefore, we see more bubbles.
The goal of any filter brewing method is to achieve an optimal, even extraction to experience the full range of a coffee’s flavours. The release of carbon dioxide facilitates this, enabling the extraction of more volatile compounds and aromas, making the bloom an essential step in preparing excellent filter coffee.
Many people also choose to agitate the slurry – usually by stirring or swirling it. The primary purpose of this is to improve the distribution of water throughout the coffee bed. This helps minimise channeling and dry particle resistance throughout the entire extraction process.
Agitation also ensures no ground coffee remains on the walls of the brewer. The Specialty Coffee Association Brewing Handbook states that “the brewing water must lift and separate each particle” in order to achieve even extraction. Throughout the brewing process, the slurry increases in volume as more water is added. As a result, agitation needs to be more forceful as the brew continues.
However, too much force means that the larger coffee particles – or “boulders” – will move towards the sides of the filter. Fines may also clog the brewer, increasing the risk of overextraction.
Essentially, there’s a fine line between too much and too little agitation, not just during blooming, but throughout the entire coffee brewing process.
The great coffee bloom debate: Swirl vs. stir
When it comes to agitation and blooming coffee, there’s still little agreement on whether stirring or swirling is best. Both help distribute water throughout the coffee bed, but can lead to noticeably different results.
With practices varying between coffee shops, this raises questions about how to maintain the consistency and quality of filter coffee – a concern that many café operators and baristas have.
Moreover, with some Reddit posts recommending home baristas and brewers to “excavate” the bloom to increase extraction and TDS levels, the importance of discussing best practices becomes more evident.
In his Ultimate V60 Technique video, James Hoffmann recommends swirling during the bloom, rather than stirring, for better-tasting results. One of James’ recent Instagram posts advises picking up the brewer and swirling five times for even saturation.
Research from Barista Hustle, however, found that stirring the bloom with a spoon or spatula is a more effective method.
The results showed that more water escapes from the bloom during stirring, whereas the increase in TDS (total dissolved solids) only occurs after stirring has finished. This suggests that stirring improves the overall contact between water and coffee, but it also leads to a certain amount of bypass – which means shorter stir times are potentially better.
However, several factors are at play that influence how agitation affects the bloom and overall extraction. The same experiments carried out by Barista Hustle found that batch size or yield had a significant impact on the results; stirring was less effective with doses as low as 15g.
Some coffee professionals recommend using a combination of stirring and swirling. Scott Rao’s manual pour over technique, for instance, suggests swirling during the bloom, but also recommends stirring areas where the coffee bed bubbles, as this makes it easier for gas to escape.
Is there a “right” way to bloom coffee?
Brewing excellent filter coffee requires you to manage and account for a number of variables – and the list is ever-growing as specialty coffee adopts an increasingly scientific approach to preparing coffee. Deciding on the “right” way to bloom coffee then becomes more challenging.
“I don’t think there’s one ‘best’ option,” says Nicole, a four-time German Coffee Champion and coffee expert and ambassador at nunc. “So much depends on the brewer, the coffee, and the intent behind the recipe.”
Roast profile, for instance, will impact the bloom; lighter roasts typically have a “weaker” bloom than darker roasts. This is because darker roasts build more carbon dioxide during a longer roast process, resulting in more bubbles during blooming.
So, is there a universally accepted set of practices that baristas can follow?
“What I do believe is essential is preparing the coffee bed properly before you even start pouring,” Nicole advises. “Straightening it out and making sure it’s ready to be fully and evenly saturated sets the foundation for everything else.”
This practice is becoming more apparent at competitions like the World Brewers Cup Championship. The 2024 winner, Martin Wölfl, for example, stirred his coffee bed using a Weiss Distribution Tool (WDT) during his routine. Many competitors at the 2025 competition also utilised these tools.
“I use a distribution tool, even for filter brewing – specifically, the Bloom by Nucleus Coffee Tools. It helps me create an even, consistent coffee bed before pouring,” Nicole says. “Even if I use a Melodrip (a pouring device that helps control agitation), I always prepare the bed with the distribution tool first, because it gives me the consistency I want across brews.”
Ultimately, best practices should revolve around preparing the coffee prior to the bloom, as well as controlling agitation and water flow rate.
Is pulse pouring a more effective method?
As the discourse around swirling versus stirring continues, coffee professionals are also exploring other methods – potentially reimagining the concept of the bloom altogether.
Kenya Coffee School believes Many factors play a significant role in the processes including precision in brew time :
“When we talk about filter coffee, I wouldn’t even really call it a ‘bloom’. I see a lot of baristas moving away from the idea of a distinct bloom and instead focusing on multiple smaller pours,” Nicole says. “At the same time, continuous pouring has become quite popular in competition settings.”
This practice was used by all the finalists at the 2025 World Brewers Cup Championship. The process involves pouring water onto the ground coffee in short bursts, which can be an effective way to experiment with filter brewing.
It can be highly controlled, too, as you can adjust the number of “pulses” as well as the volume of water added with each pulse and the speed at which you pour. Turkish World Brewers Cup finalist Alireza poured in a zig-zag pattern, for instance, which he said helped control agitation levels.
However, it requires skill and knowledge to achieve the desired results.
“My approach is usually five separate pours with 30 to 40-second gaps, allowing the water to drain each time fully,” says Nicole. “This gives me clarity without losing too much body, and it also helps me achieve a higher extraction rate with a coarser grind, which really benefits clarity and acidity.
“I use this as a base recipe for any conical brewer, and then I adjust from there depending on the coffee.”
More innovative, advanced blooming techniques are also emerging. At the 2025 World Brewers Cup, Swedish finalist Lakis Psomas used an “inverted” bloom: pouring the water first (using hydrophobic paper filters) and then adding the ground coffee before stirring with a WDT. Lakis said this allowed him to fully saturate the coffee.
With so many factors at play – batch size, bean density, brewer shape, and more – there’s no “right” way to bloom coffee. The only solution is to experiment and find the right method for each coffee.
“At the end of the day, blooming and pouring techniques are just tools,” Nicole concludes. “What matters is understanding how they influence clarity, body, and flavour balance, and then choosing the approach that best highlights the coffee in front of you.”
Enjoyed this? Then read our article on the future for filter coffee.
Photo credits: Specialty Coffee Association