How Much Water to Bloom Coffee: The Ultimate Guide

how much water bloom coffee

You’re enjoying a nice cup of black coffee in your local café. You think to yourself, “This tastes great!” Then you begin to wonder, why making that same mug at home never tastes the same? Why is it always more bitter? It’s probably because it wasn’t bloomed properly. We’re going to look at what blooming is, why it occurs, why it should occur, and approximately how much water is needed to bloom coffee.

So how much water is required to bloom coffee? The answer is that it depends on the way you brew your coffee. For most applications, however, you should add 2 to 3 grams of water per gram of coffee. This will ensure the coffee releases its best flavors when you brew it.

In this article, we’ll go over the many different ways to bloom your coffee as well as why blooming coffee can enhance its flavor.

Let’s get to it!

What Is Coffee Bloom?

You may have spotted coffee bloom randomly as you were pouring some water over your ground coffee. It resembles a thick layer of light brown foam with numerous bubbles. It looks a bit like espresso crema, but with a lighter texture and more bubbles.

Author Note: When you pour hot water over the coffee grounds, they start to expand while releasing their internal gases, namely carbon dioxide (CO2). As these gases get vented to the surface, they create an expanding foam, which resembles a blooming flower. How romantic!

Although COprolongs the coffee’s shelf life, you want it gone before brewing your beverage. Otherwise, your coffee will end up tasting sour or bitter.

But blooming isn’t only about preventing sour taste, it’s also essential to extract all of your coffee’s satisfying aromas. If coffee is not bloomed before brewing, the gases that should have been released earlier will interfere with the water, preventing it from steeping the coffee’s oils.

When coffee blooms, it is an indication that your coffee is fresh, which is good. If it doesn’t bloom at all, the beans have probably become stale. This may drastically affect how your coffee tastes.

The Relation Between Roasting and Blooming

Horizontal shot of a man in a red apron placing boiling water in a French press to prepare coffee

Roasting is the final step in the coffee creation process, right before packaging and distribution. Roasting converts the beans’ organic substances to CO2. That gas will slowly leak from the whole beans immediately after roasting. As soon as you grind the beans, the degassing rate will soar up, eventually reaching the highest value after adding hot water.

Top Tip: Keep in mind that CO2 should remain within the bean for as long as you store the coffee. This is because CO2 prevents oxygen from coming in contact with the bean’s other aromatic and flavorful compounds. If oxygen reaches these compounds, the coffee will become stale.

How to Bloom Your Coffee

There are several ways and methods to bloom your coffee. No one way is better than the other. the choice entirely depends on your preference, and what you have available.


Brewing coffee with the pour-over technique is the easiest option since its requirements are minimal. All you’ll need is a cup, a filter, and a funnel. The method involves pouring a steady stream of hot water on ground coffee.

  1. Place your coffee grounds in a pour-over filter atop a cup.
  2. Wet the coffee grounds slowly by pouring in a circular motion (we’ll discuss the exact amount of water below).
  3. Wait about half a minute until the grounds bloom.
  4. Resume your brew.

French Press

Because a French press comes with a built-in filter, it’s favored by users who don’t like to hassle with cleaning. The process entails separating coffee grounds from the beverage by pressing down the filter.

  1. Place your coffee grounds in the French press pot.
  2. Wet the coffee grounds.
  3. Wait for the grounds to bloom.
  4. Stir the grounds, so everything is saturated and wet.
  5. Resume your brew.

Automatic Coffee Maker

If you have a coffee maker, don’t fret. You can still achieve the blooming needed to take your drink to the next level. The idea is to bloom the grounds manually before letting the coffee maker take over the rest of the brewing process.

  1. Place the filter in your coffee maker’s basket.
  2. Place the coffee grounds in the filter.
  3. Wet the grounds in a circular motion.
  4. Wait for the grounds to bloom.
  5. Resume your brew.

How Much Water to Bloom Your Coffee?

Blooming coffee grounds requires only a small amount of water, just to wet them. Ideally, you should pour 2–3 grams of water onto each gram of ground coffee. For example, a coffee serving of 15 grams would need about 30 grams of water to bloom.

However, there are more elements to take into consideration when deciding on this ratio. We’ll discuss them all one by one in the following sections.

Bean Hardness

Pouring Chinese green tea into gaiwan with hot water

There are more than 120 species of coffee. Every type of coffee bean differs in shape, color, taste, and hardness. The main two coffee plant varietals are Arabica and Robusta.

Author Note: Arabica coffee beans aren’t as hard as Robusta beans. The harder the bean, the more difficult the degassing process becomes. So to speak, if you’re using Robusta beans, you’ll need more water to make its grounds bloom.

But when we say more, we are talking about a tiny change. Instead of using a ratio of 2 grams of water to each gram of coffee, it should be 3 to 1.

Roasting Level

Roast level simply refers to the point at which roasting the coffee was stopped. It may be after the beans have cracked, or before.

The level of roasting impacts the volume of gases that have been released from the beans. The longer the beans are roasted, the more gases they’ve lost.

By extension, beans that have had an extended (dark) roast won’t need as much water to achieve blooming.

Coffee Grounds

Naturally, the amount of grounds used is directly proportional to the amount of blooming water.

The freshness of the grounds also impacts the volume of water necessary to achieve blooming. Fresh coffee grounds will bloom more, hence needing more water.

Temperature and Humidity

Hot and dry atmospheres accelerate the natural degassing process of coffee beans and grounds. Keep in mind that if this is where the coffee has been sitting, it won’t need as much water to bloom. This is because some of the gases have already been released, so blooming will be quicker.

Humid regions, on the contrary, keep the gases intact for a longer period of time, enhancing the blooming quality. However, the humidity may also encourage the growth of mold and fungi.

As such, it’s better to keep your coffee stored in a balanced region —  not too humid, nor too dry.

How Long to Keep the Coffee Blooming?

After wetting the grounds, wait for about half a minute for the foaming to subside. Add a bit more water to see whether the coffee will resume blooming.

More blooming either means your coffee was extremely fresh, or that you didn’t add enough water the first time. Remember that no bloom at all means your coffee has become stale, and you’ll need a new batch.

When your coffee grounds are done blooming, you may add more water according to the number of servings you plan on having.

Why Should You Bloom Your Coffee?

As we’ve established, coffee needs to bloom so that we can avoid the sour taste that is caused by the presence of CO2.

When we bloom coffee, we allow CO2 to be degassed from the coffee grounds. If the grounds aren’t properly degassed, CO2 will hinder proper contact with water. This happens because, while brewing, CO2 repels water from the grounds, creating turbulence. That, of course, will stand in the way of extracting all the delicious coffee flavors. The inhibition of these flavors also adds to the acidity of the brew.

Author Note: However, this sour acidity is majorly notable in black coffee. If you’re accustomed to flavoring your coffee with milk, sugar, or packaged creamers, blooming may not make much of a difference for your beverage.

How to Store Your Coffee

European woman brews coffee at home in her kitchen and enjoys her morning

As we’ve established, blooming is more effective in beverage quality if the coffee is fresh. What if you buy a new batch that you don’t intend to use up in a day? Knowing how to properly store your coffee is essential to have it attain freshness for as long as possible. Here is how:


Store your coffee in a dry, shaded area to avoid exposure to direct heat. Why? Well, heat actually brews the coffee slowly, which will add an odd, undesirable flavor.


Keep the coffee stored someplace cool, away from a humid environment. Humidity can cause the coffee to grow mold and fungi.


Make sure the coffee container is airtight. This is to preserve the coffee from oxidation and protect it from getting flavored by nearby foods.

Wrapping Up

Blooming coffee is not a necessity; it’s entirely up to you. If you want to dial down the sourness, you can’t skip this process.

Blooming allows coffee grounds to degas and release all the pent-up CO2 that gives it an acidic edge. You want to add water 2 or 3 times the amount of coffee and wait about half a minute for the foaming to fade. Afterward, you can resume your brew as you naturally would.

Stay caffeinated friends!

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