Should Pour-Over Coffee Blooming Time Be Counted from the Start or End of Water Pouring? Is Blooming Considered a Separate Phase in Coffee Brewing?

"So first, we pour twice the weight of the coffee in water, then wait thirty seconds for the bloom."

This is the step FrontStreet Coffee always performs at the start of a brew - the bloom. Under normal circumstances it is never skipped, because blooming makes it much easier to brew a delicious cup.

Many of you have probably wondered why the bloom must last 30 seconds and use twice the coffee's weight in water. Would a little more or less time - or water - really not work?

Of course it would! Neither the time nor the water amount is bound to any hard standard - you are free to adjust both. But before changing the parameters, you need to understand what blooming is for and why these two values are recommended. Only then will you know when to adjust the time and when to adjust the water.

The First Purpose of Blooming: Degassing

As everyone knows, the primary purpose of blooming is to let the coffee bed degas. Freshly roasted beans hold a great deal of trapped carbon dioxide, and that CO2 is a double-edged sword: on the plus side, it slows the loss of flavor compounds and extends the beans' flavor window; on the minus side, during brewing it blocks hot water from reaching those compounds, acting like a wall between the water and the flavors.

Brew very fresh beans straight away without degassing, and the hot water stalls against that wall of CO2, extracting less. FrontStreet Coffee ran a dedicated experiment: the same beans, the same parameters (total brew time held at two minutes), with the only variable being whether the coffee was bloomed.

The unbloomed coffee extracted at 13.53%; the bloomed coffee reached 17%. That gap shows just how much carbon dioxide matters to extraction. Hence the bloom: to vent the CO2 that would otherwise hinder extraction. So why 30 seconds?

Strictly speaking, there is no requirement that the bloom be exactly 30 seconds - 25 or 35 seconds also works. But 30 seconds has the broadest applicability, giving sufficiently complete degassing regardless of how old the beans are. Shorter than 30 seconds, and very fresh beans with lots of gas may not degas fully, which hurts extraction. Beyond 30 seconds, the grounds keep releasing gas but the effect diminishes sharply as the degassing rate slows. So 30 seconds is a safe middle ground: long enough to avoid under-degassing, short enough not to waste time.

When should you use a different bloom time? Simple: whenever the CO2 content is unusually high or low. With beans so fresh that gas is abundant, 30 seconds may not vent everything, so you can extend the bloom by about 5 seconds to release more CO2 before the main pours, letting the hot water dissolve flavor compounds more effectively. With beans past their prime and lower in CO2, there is no need for a long bloom - just shorten it based on how quickly the coffee bed drains and loses its sheen (again, about 5 seconds).

The Second Purpose of Blooming: Saturation

The second purpose is saturating the grounds - wetting the bed evenly so the grounds connect and later pours are less likely to channel and extract unevenly. But remember, blooming's main job is degassing to set up the extraction that follows. If you use too much water at this stage, the compounds that water pulls out will be comparatively few - far less than the same water would extract during the main pour.

Because the grounds have not yet degassed, hot water cannot extract efficiently, so you want to keep the bloom water to a minimum. But you cannot shrink it indefinitely, or the grounds will never fully saturate - especially those at the bottom of the dripper. The rule, then: less, but not too little. Conveniently, dry grounds absorb a known amount of water, which is exactly why twice the coffee's weight became the standard: it guarantees full saturation while wasting as little hot water as possible.

Like the timing, the bloom water amount is only a sensible default, not a law of nature - adjust it to suit the beans. In practice there is rarely any need, since the standard amount is well judged. The main exception is a complete beginner whose pouring technique cannot yet saturate the whole bed with so little water; in that case, simply add about 10ml to the bloom.

FrontStreet Coffee Recommendation

Blooming theory deserves a good bean to practice on. Three FrontStreet picks that reward careful pouring:

• FrontStreet Yirgacheffe Guodingding - the classic first stop for pour-over newcomers. Vivid citrus, berry, and floral aromatics with a green-tea-like sweetness on the finish; its acidity is soft and bright, like fruit rather than vinegar - easy to love and easy to brew.
• FrontStreet Ethiopia Huakui - a natural-process standout with pronounced tropical fruit: strawberry, passion fruit, jackfruit, even lychee. Distinctly sweet, almost no bitterness, silky and juice-like - often described as "the coffee that doesn't taste like coffee," perfect for winning over people who dislike traditional coffee's bite.
• FrontStreet Panama Esmeralda Red Label Gesha - the legendary benchmark. Elegant jasmine florals with citrus, bergamot, and fine black-tea notes, a clean and transparent cup, and a long, layered finish. Pricier than ordinary specialty coffee, but still one of the ultimate experiences for coffee lovers.