What is Coffee Bloom and How It Impacts Taste – The Theory Behind It

What is Coffee Bloom – How to Bloom for Different Brewing Methods?

Guest Post by: Coffee Style Today

We spend so much time looking for the most delicious coffee. And sometimes we also talk about how coffee boosts physical and mental energy. But not much time or effort is spent on coffee blooming. But first, what is coffee bloom?

In order to prepare the freshest cup of coffee of your life, and to have to repeat that every single day, you need to understand this particular aspect of the brewing process. Unfortunately, only a small part of the coffee-sipping community truly recognizes its importance. So allow us to tell you all about it!

Coffee Bloom Explained – What Is It and What Causes It?

Mainly heard of for the pour-over brewing method, the words “coffee bloom” means pouring a small quantity of hot water over the coffee grounds and letting that stew for about half a minute before you start brewing.

During those 30 seconds, coffee grounds swell and bubbles take form on the surface – this is what you see. But what you don’t or can’t see is the release of carbon dioxide from the coffee beans.

Carbon dioxide becomes a part of coffee beans during the growing stages. And the gas starts to escape at the time of roasting. The longer the roasting process, the more the release of carbon dioxide. This means dark roasts have the least amount of CO2.

After roasting, coffee beans are ground, right? That’s when there’s an increase in their surface area, correct again? And this paves the way for more degassing. No wonder it’s highly advisable to grind coffee beans right before brewing in order to keep the most amount of freshness intact.

What you should probably know about natural degassing is that the process also eliminates the coffee flavors and not just carbon dioxide. 

Needless to say, carbon dioxide should be preserved right until brewing begins. Once brewing starts, CO2 turns from friend to foe. Because, during brewing, carbon dioxide can make your coffee taste sour. And it even keeps the delicious, flavorful compounds of coffee from getting extracted when they come in contact with hot water.

And that is why it’s so important for your coffee to bloom for half a minute prior to brewing. You can add another 30 seconds to allow all the gas to be completely released.

Just so you know, coffee beans, post-roasting, are degassed. But you still have to do the blooming part in order to finish what’s started.

Freshly Roasted and Freshly Ground Coffee Matters

Once the roasting process begins, carbon dioxide starts to release. And this goes on for quite sometime post-roasting. In the first week, most of the CO2 is released. This means the majority of the flavor-giving volatile compounds escape. Then the rate of degassing slows down after those initial days.

One more thing you should know is that when you grind coffee beans, the increased surface area makes way for faster degassing. Now you understand why coffee beans should be freshly ground right before brewing?

Even the Storage of Coffee Beans Matters

Both packaging as well as storage of your coffee beans play a part. That’s what airtight containers are for. They keep the gases contained, which lowers the rate of the release of carbon dioxide. Plus, needless to say, the airtight lid makes sure no external elements like oxygen and moisture are allowed to enter.

As for the packaging, more often than not, top coffee brands sell their coffee in vacuum-packed pouches or bags that feature a one-way valve for the slow release of carbon dioxide.

Other Factors That Matter

Aside from roasting, grinding, and storage, the following variables also affect the release of carbon dioxide…

• The harder the coffee beans, the greater the density, right? So this increases the chances of the release of carbon dioxide.
• When the temperature at which your coffee beans are stored is higher, more gases are allowed to escape.
• What about humidity levels? When it’s dryer, more carbon dioxide is released. And when the humidity is higher, so is the formation of fungus and mold. Find the middle ground here.
• Dark roasted coffee beans contain the least amount of carbon dioxide because of the hotter, longer roasting process.
• Even the origin of the coffee matters. Because coffee growing in some regions degasses more than the others.

When Is Coffee Blooming Necessary?

It’s quite obvious, isn’t it, that not every brewing method benefits from coffee blooming. At least not as much as is the case with the pour-over technique. With pour-over, hot water and coffee beans remain in contact for a very short span of time to facilitate blooming. And this contact time is longer when the brewing method involves using a French Press.

So what’s the exception? It’s cold brewing. And why do you think that is? Simply because hot water is not a part of this particular brewing technique. But you can bloom the coffee grounds using hot water prior to preparing your cold brew. And this means making the most flavorful cold brew.

How to Bloom Coffee for Different Brewing Methods

The basics remain the same, which consist of pouring a small amount of hot water over the coffee grounds just to make them damp. And then letting it sit or bloom before you actually start brewing. But how you go about it is based on what type of coffee maker you’re using.

Also, no matter the brewing technique, if your coffee grounds don’t take on the bloom form (swelling of the coffee grounds and formation of bubbles on the surface) when you pour hot water over them, it’s most likely they’re stale. And this means you may not get a full-flavored, rich brew.

1. Pour-Over

The small quantity of hot water you pour over your coffee grounds should be done in a circular motion. Start from the outside, then work your way toward the center.

Make sure to use only a little bit of water. The goal is to soak the coffee but not allow it to drip through. Let the grounds bloom for a minute and then go on with the brewing process.

2. French Press

In much the same manner, you can prepare a quick, single cup of French Press coffee. For that, pour hot water over your favorite coarse ground coffee. The blooming time is just 20 seconds here. Now stir the coffee grounds using a spoon. And then complete the remaining process.

3. Automatic Drip Coffee Maker

After adding your coffee into the coffee maker’s filter basket, pour some water over the grounds. The best blooming time, in this case, is around 90 seconds.  After that, begin the normal brewing cycle.

4. Cold Brew

You can try experimenting with the method of hot bloom/cold brew. Add coffee grounds into the container, then pour the small amount of hot water, and let your coffee bloom for 30 to 45 seconds.

After that, add cold water to carry on with the rest of the brewing process, which demands brewing for around 12-24 hours.

5. Manual Espresso Machine

Why shouldn’t you make the most of the magical coffee blooming process whenever you can!

In the case of espresso coffee makers, coffee blooming is actually known as pre-infusion. And what it does is make the grounds damp along with swelling up the coffee within the portafilter. The latter part, in particular, increases the surface contact between hot water and the grounds. In short, it’s responsible for preparing a richer flavor.

But what about when you’re using a manual or lever-controlled espresso machine? How do you pre-infuse or bloom then?

Just lift that lever until the thing latches into place and then hold on for around 15 seconds for letting hot water fill up the filter basket. Finally, perform a halfway pull of 15 seconds on the lever. This means 30 seconds in total. And you can do the same 30-second lever pull once again.

Frequently Asked Questions

Is the Hot Water for Blooming A Part of the Total Water Ratio?

Yes, the amount of water you use, even though little, is a part of the total ratio or weight of water used for brewing. But then you can do it both ways, just let your taste buds decide which option is more delicious.

Why Doesn’t My Coffee Bloom?

The most common reason is stale coffee beans. Maybe you didn’t buy freshly roasted coffee and/or did not store it in an airtight container away from light, moisture, heat, and oxygen.

One more thing, just for your information, dark roast coffee beans may not show the blooming form as noticeably as medium and light roasts, but they still swell slightly when hot water is poured over them. And that’s an indication of freshness indeed.

Conclusion

If you have an automatic coffee maker that prepares your brew right before you wake up in the morning, you lose on the magic of coffee blooming. But then, on the other hand, if you genuinely care about every part of the brewing process, be it manual or automatic, then it’s only in your best interest to pre-wet the coffee grounds.

But there’s a right way to go about it. And we have discussed all of that in this article, apart from explaining what coffee bloom really is and the factors that affect the release of carbon dioxide.

Author Bio

Explaining how to prepare the most delicious coffee at home is what coffee experts at Coffee Style Today know how to do best. Just like this post, they publish articles to help you upgrade your coffee experiences with what you already have.