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What do we mean when we brew coffee by immersion, infusion, percolation, and decoction?
What is the difference between coffee immersion, infusion, percolation, and decoction?
Well, sorry to complicate this but there is a bit of confusion when we use these terms when we talk about brewed coffee.
In this post, we will try to explain the differences in these terms and how we can use them when we talk about brewing coffee.
So let us now look at these primary brewing methods in more detail.
What Is Infusion or Immersion Coffee Brewing?
In infusion brewing, the coffee grounds are completely immersed in hot water (or cold water when making cold brew coffee).
You can see here there we used the word ‘immersed’ and this is where the confusion arises.
Immersion is what you do to the coffee grounds to create an infusion or decoction (see later).
You immerse the coffee grounds in hot (93–96 °C) or cold water to make an infusion of the coffee. The resulting infusion is your brewed coffee.
This reflects the Wikipedia definition of infusion as: “the process of extracting chemical compounds or flavors from plant material in a solvent such as water, oil or alcohol, by allowing the material to remain suspended in the solvent over time (a process often called steeping). An infusion is also the name for the resultant liquid.”
Immersion and infusion are not the same processes but immersion is often used as a synonym for infusion. As you can see from the Wikipedia definition immersion is also known as steeping.
Sometimes the term infusion is incorrectly used to mean percolation (see below).
When you use infusion brewing, it is like the coffee grinds are taking a bath!
When you use the infusion brewing method you usually first agitate the grounds and water for a little while and then let the coffee immerse (steep). This helps extract more of the coffee flavors.
Infusion coffee brewing methods may or may not use paper filters. However, most infusion methods will use a filter of some sort. The exceptions to this are cowboy coffee, Turkish coffee, and cupping where the grinds are usually left in the brew.
The following brewing methods use infusion to extract coffee from ground coffee beans.
- Clever Brewer
- French Press
- Cowboy Coffee
- Turkish Coffee (Cezve Brewer)
- Aeropress Brewer
- Siphon/Syphon. Also called vacuum coffee
- Cupping (coffee is left in the cup after water is added. This is used when judging coffee quality in a competition)
The brew time varies depending on the brew method, grind size, and personal taste.
Usually, a French Press has a 4-minute brew time but a cold brew can be 36 hours or more.
Please read our similar posts on infusion brewing methods…
Advantages of Infusion (Immersion) Coffee Brewing
Some of the advantages of infusion coffee brewing include…
- Most devices use a filter to prevent coffee insoluble from passing into the final brew. A paper filter will also absorb and remove coffee oils from the final brew. This will result in a less viscous coffee and less ‘heavy’ mouthfeel.
- Less fiddly and easier to use
- Doesn’t require sophisticated brewing gear
- Filter paper can be used to remove some coffee oils
- Less need to closely monitor the brewing process compared with infusion brewing
- Consistency between brews provided you carefully choose an appropriate brew time and manual pressure if using manual pressure equipment such as a French Press
- Brews a bold, rich, and heavy coffee
- Easier to make cold brew coffee compared with the infusion method
- Can be diluted to taste if you have an initial bolder brew
Disadvantages of Infusion Coffee Brewing
Some of the disadvantages of infusion coffee brewing include…
- Incorrect choice of brew time. The coffee is left to steep in the water for too long or too little. This leads to over extraction or under extraction of the coffee respectively. Extraction slows down as the immersion time continues because the coffee gradually becomes more saturated and this prevents further solubles from leaving the coffee grinds.
- Some infusion methods such as French Press and the Aeropress use manual pressure to separate the coffee liquid from the coffee grinds. However, too much pressure may result in solids or fine grain solids passing through the filter and ending up in your cup.
- Inconsistent coffee brew if you use incorrect manual pressure or brew time
What Is Percolation Coffee Brewing?
In percolation brewing, the coffee grounds are not completely immersed but have hot (or cold) water passing over and through them.
Percolation comes from the Latin word percolare, which means “to strain through.”
Percolation is like the coffee grinds are having a shower!
Percolation coffee brewing methods tend to be a more efficient extraction method compared with infusion coffee brewing methods. This is because the constant flow of water over the coffee grinds continues to extract coffee from the ground coffee.
Percolation methods need to use a filter to prevent the coffee grounds from being immersed in water and to prevent coffee grinds from entering the final cup of coffee.
The following brewing methods use the percolation method to extract coffee from ground coffee beans.
- Drip Coffee (usually automated coffee machines)
- Chemex (could also be considered pour-over coffee)
- Pour-over Coffee (also called Filter Coffee) using brewers such as V60, Kalita, and Melita Bentz
- Moka Pot
Please read similar posts on percolation coffee brewing methods…
In some percolation brewing methods, water is poured to wet the grounds to bloom the coffee. The bloom is a consequence of air released from the wet coffee grounds.
During the bloom the coffee grounds are percolated with water for a little while. This is sometimes confusingly called a ‘pre-infusion’. The pre-infusion helps extract the flavors from the coffee grounds.
Using the term ‘pre-infusion’ adds to the confusion of terms used for coffee brewing because there is no ‘infusion’ when extracting coffee using percolation.
After the pre-infusion, more water is slowly added either automatically (as in an automatic drip coffee machine) or manually (as in a manual pour-over coffee maker).
Gravity pulls the water over and through the coffee grinds in the filter.
The clear filtered coffee is then collected in a carafe.
Gravity percolation coffee brewing results in a complex coffee with a lot of flavor and depth.
Brew times vary depending on the brew method and personal taste. Generally, brew time varies from seconds (for an espresso) to minutes.
Espresso uses external pressure (up to 15 bar), not gravity, to percolate water through coffee grinds.
Advantages of Percolation Coffee Brewing
Some of the advantages of percolation coffee brewing include…
- More efficient extraction method compared with immersion coffee brewing methods. Essentially, infusion brewing doesn’t suffer from the saturation effect seen in immersion brewing because there is a constant stream of fresh water through the coffee grinds.
- You need a little less ground coffee per brew with infusion coffee brewing compared with immersion coffee brewing methods.
- The filter used in infusion brewing traps some of the coffee oils extracted from the coffee and prevents insoluble coffee grinds from entering the final cup of coffee
- Results in a clean, complex, slightly acidic, and flavorsome coffee
Disadvantages of Percolation Coffee Brewing
Some of the disadvantages of infusion coffee brewing include…
- Controlling the rate of water poured into the coffee. Poor control of water rate leads to poor extraction. Poor control stems from inexperience when using a gooseneck kettle for pour-over coffee, faulty drip mechanisms, or incorrect drip settings.
- Channeling. This is when water is misdirected into channels that form in the coffee bed. This is often the result of an uneven bed of coffee grinds. The general result is that the coffee is under-extracted.
- Temperature instability. A near-constant and stable temperature is needed for the best extraction of coffee. However, the size, shape, and material of the infusion coffee brewing method can cause temperature differentials which vary the temperature of extraction.
- Compacting coffee bed. If you use a coffee grind that is too fine then it may cause the coffee bed to compact, restrict water flow, lead to longer brewing times, or overflow from the coffee basket.
- Inconsistent brew. Given all the points above infusion, brewing is difficult to reproduce and may lead to inconsistent brews.
Is Coffee a Decoction?
What is a decoction?
According to Wikipedia “Decoction is a method of extraction by boiling herbal or plant material (which may include stems, roots, bark and rhizomes) to dissolve the chemicals of the material. Decoction involves first mashing the plant material to allow for maximum dissolution, and then boiling in water to extract oils, volatile organic compounds and other various chemical substances”
Consequently, coffee may be considered a decoction even though coffee is not usually extracted with boiling water. Coffee is usually extracted with water between 93–96 °C (199–205 °F).
However, not many people refer to coffee as a decoction.
What Does Coffee Brewing Do?
The whole point of coffee brewing, regardless of the method of brewing, is to extract the soluble components of the roasted coffee beans to make a tasty, aromatic, and flavorful coffee drink.
The components of coffee we extract through brewing coffee include…
- Acids (which give the coffee sour, sweet, and fruit flavors)
- Caffeine (Have you tried our caffeine calculator?)
- Chlorogenic acid
- Coffee oils (which gives the coffee viscosity)
- Sugars (which give the coffee sweetness and viscosity)
- Other solubles
The extraction of all of these components from ground coffee beans can be separated into soluble and non-soluble. The extracted solubles are referred to as Total Dissolved Solids (TDS).
The efficiency of extraction of all of the components is usually calculated from the brew ratio and the TDS.
TDS determines the ‘strength’ of a coffee. Strong coffee has a higher TDS and weak coffee has a low TDS. However, the TDS doesn’t necessarily indicate a better coffee or a good extraction.
Brewing coffee is about achieving a consistent taste that explores the natural flavors of the coffee beans.
However, this is often difficult to achieve because there are many variables that affect the extraction of coffee beans with either immersion or infusion brewing methods.
These variables include the type of coffee bean, roast level of the coffee bean, coffee grind, water, temperature, and brew ratio.
Type of Coffee Bean
The two main types of coffee beans that are often quoted are robusta and arabica.
However, there are hundreds of varieties of coffee beans and each has unique flavor characteristics.
This is one reason that makes drinking coffee so interesting.
It is wonderful to explore this diversity of coffee bean tastes and flavors.
Raw or green coffee beans are roasted before any brewing technique is used to extract the components.
Three roast levels of light, medium, and dark are often quoted in many posts but there can be many variations of roast.
The roast affects the look, flavor, and taste of the brewed coffee.
The first step for brewing coffee is to grind coffee beans to produce a range of grind sizes which are often labeled as fine, medium, or course. You choose the grind size to suit the brewing method. You grind the coffee to increase the surface area of coffee that can be exposed to the different brewing methods.
Keeping the coffee grind consistent is important in brewing coffee by any method.
Coffee is brewed from ground coffee using either the immersion or infusion brewing methods.
Generally, a fine coffee grind requires a shorter brew time and a coarse coffee grind requires a longer brew time. The grind you choose will depend upon the brewing method you use. For example, a French Press (an immersion method) requires a coarse grind whereas an Espresso (an infusion method) requires a fine grind.
If you find that your coffee is thin, weak, or sour, then you may like to experiment with a finer grind for your brew method. In contrast, if your coffee is bitter or harsh you may like to experiment with a coarser grind.
The quality of the water you use is important for both immersion and infusion coffee brewing methods. We have discussed the importance of water in a previous post.
The goodcoffeeplace is a member of the Specialty Coffee Association (SCA) and we often refer to SCA guidelines.
The SCA says that the ideal temperature range for brewing coffee is 195°F–205°F (90.5°C–96°C) when water contacts ground coffee.
However, other people may have their preferences. For example, Aeropress Championship coffee brewing recipes usually require the temperature of water to be 176°F (80°C).
Regardless of the recommended temperature, you choose for your brew it is important that you keep the temperature stable throughout the brewing process. Variations in temperature cause inconsistent extraction of the coffee.
A coffee brew ratio is the ratio of ground coffee to water used with a brewing method.
The usual brew ratio for coffee brewed with an immersion or infusion method ranges from 1:15 to 1:18. For example, a ratio of 1:16 means that for 1 gram of ground coffee you add 16 grams of water.
Espresso has a different brew ratio because it uses pressure rather than gravity to extract coffee. The brew ratio for espresso is usually 1:2.
However, you can experiment with different brew ratios with various coffee brewing methods and choose the one that suits your taste.
Immersion and infusion coffee brewing techniques include a variety of coffee brewing methods that use slightly different techniques or coffee brewing gear.
Frequently Asked Questions (FAQ)
What Type of Coffee Beans to use for Infusion and Percolation Coffee Brewing?
You could choose single-origin coffees with acidity for infusion coffee brewing and slightly darker and heavier coffees for immersion brewing.
We have mentioned some coffees that you can use for French Press in a previous post.
However, the choice of coffee beans really depends upon you.
You find the coffee that suits your taste for the brewing technique that you use.
Is a Coffee Percolator an Infusion or Percolation Coffee Brewing Technique?
Why is a percolator in the list of infusion methods and not in the list of percolation methods? Well, despite its name I think coffee from a percolator is more of an infusion method because the coffee grounds are steeped in recycled coffee. You can find more about this in my post which discusses the difference between a percolator and a Moka pot.
Which Brewing Method Should I Choose?
It is up to you!
Consider your taste preference, your coffee knowledge, your skills, your budget, and the time available.
Immersion brewing is usually easier and doesn’t require sophisticated coffee gear.
Percolation coffee brewing can give a more complex-tasting coffee.
If you want to learn more about brewing coffee then don’t be afraid to experiment. You can get tips from posts here on goodcoffeeplace and on many other places on the internet.
You may also like to consider some online training with one of the best online training courses.