The Importance of Espresso Brew Temperature: Unlocking the Perfect Shot
In this post, we’ll dive into why brew temperature is so critical, how it affects extraction, and how the Brua3 Max will help you make a perfect cup every time.
Understanding Brew Temperature
When we talk about brew temperature in the context of espresso, we are referring to the temperature of the water used to extract the coffee from the grounds. Water temperature, as it passes through the coffee grind, has a profound effect on the efficiency of the extraction process, influencing how compounds like acids, oils, and sugars are dissolved and released into the final shot.
In most electric espresso machines, the brew temperature is usually set between 88°C to 96°C. While this may seem like a small range, several degrees outside this range can significantly impact the flavour of the espresso. Too hot, and the coffee can become over-extracted, leading to bitterness and harshness. Too cool, and the extraction can be underwhelming, resulting in a weak and sour cup.
The Brua3 Max isn't electric and won't heat the water for you, so it's important to remember to use boiling water when brewing. The components of the Brua3 will always absorb a small amount of heat (even after a preheat) and some heat will also be lost to the air, so starting with 100°C water allows for this and results in ideal brew temperatures of 88-94°C.
The Science Behind Brew Temperature
When hot water is forced through finely ground coffee, it dissolves soluble compounds, such as oils, acids, and sugars, from the grounds. The process isn’t linear—different compounds are extracted at different temperatures.
- At lower temperatures (around 88°C), water is less effective at extracting the full range of compounds from the coffee grounds. The extraction tends to favour more acidic and sharp flavours, often resulting in a sour taste due to the incomplete breakdown of sugars and oils. These flavours can be pleasant in some contexts (for example, with lighter roasts), but they may not offer the depth and complexity that a properly balanced espresso requires.
- At higher temperatures (around 93°C), water is more effective at extracting a broader spectrum of flavours. The result is a fuller, more balanced shot with a richer mouthfeel. However, when the temperature exceeds 96°C, the water can begin to extract excessive bitterness from the coffee grounds, overpowering the more delicate flavours and resulting in an unpleasant, burnt taste.
The Ideal Temperature for Espresso
While there’s no universally “perfect” brew temperature that works for all types of beans or every palate, the consensus among professional baristas and espresso aficionados is that between 90°C to 93°C is the sweet spot for most espresso shots.
- 90°C: This is on the lower end of the ideal range and can be beneficial for lighter roasts, which tend to have brighter, more acidic flavours. The lower temperature accentuates these characteristics without extracting too much bitterness, offering a delicate and vibrant shot.
- 93°C: Slightly higher temperatures are often used for darker roasts, as they extract more body and sweetness from the coffee. The temperature of 93°C tends to produce a more balanced, full-bodied shot with chocolatey, nutty, and caramel notes that complement the darker flavours of the beans.
How Brew Temperature Affects Extraction
The temperature of the water has a direct impact on how effectively the coffee grounds are extracted. Let's break down the extraction process and how temperature plays a role.
1. Solubility of Coffee Compounds: Coffee solubles such as caffeine, chlorogenic acids, lipids, and sugars dissolve at different rates depending on the water temperature. The higher the temperature, the more quickly these compounds are dissolved into the water. At too low of a temperature, fewer of these compounds are extracted, resulting in under-extraction, which leads to sourness and a lack of body. The insulated brew chamber of the Brua3 Max combats under-extraction by reducing heat-loss and maintaining ideal brew temperatures.
2. Acids vs. Bitter Compounds: At lower temperatures, the extraction tends to favour the more acidic compounds in coffee, while higher temperatures extract more sugars and bitter compounds. The challenge is to find the right balance between these two types of compounds. If the water temperature is too hot, it will over-extract bitter compounds, leading to a shot that tastes burnt or astringent. On the other hand, if the water is too cool, the coffee may taste thin, sour, or underdeveloped.
3. Balance and Complexity: A good espresso shot has a balance of acidity, sweetness, and bitterness, with the bitterness playing a supporting role rather than dominating the flavour profile. By adjusting the brew temperature, you can control this balance to bring out the best in the coffee’s inherent flavours. The goal is to find the temperature that brings out the complexity and depth of the beans without emphasising any one flavour too much.
The Effects of Brew Temperature on Crema
One of the hallmarks of a well-pulled espresso shot is the crema—the golden, frothy layer of foam that sits atop the espresso. Brew temperature plays a significant role in the formation of this crema.
- Too hot: When the brew temperature is too high, the crema can become thin and overly bitter, losing its rich texture and aroma.
- Too cold: On the other hand, water that’s too cool will produce a thinner, less stable crema that lacks the characteristic golden hue and sheen. The crema may also dissipate more quickly.
The ideal brew temperature ensures that the coffee oils emulsify properly, creating a stable and rich crema that carries the aromas and flavours of the espresso. Proper crema not only enhances the visual appeal of the shot but also contributes to the overall mouthfeel and complexity of the espresso.
Adjusting Brew Temperature for Different Beans
Not all coffees are created equal, and different beans respond better to different brewing temperatures. The roast level, origin, and freshness of the beans all influence how temperature affects the extraction.
- Light roasts: These beans are typically more acidic and delicate, so a lower brewing temperature 90°C will help preserve their bright, fruity notes without over-extracting the acidity.
- Medium roasts: Medium-roast beans tend to have a more balanced profile, and a brewing temperature of around 93°C is ideal for extracting both the sweetness and the more complex flavours of the coffee.
- Dark roasts: Darker beans have less inherent acidity, and higher temperatures closer to 94°C can help pull out the body and sweetness, enhancing the chocolatey and caramel notes without emphasising bitterness.
Altering the preheat is a great way to adjust the brewing temperature using the Brua3 Max. A speedy preheat will target the lower temperature brewing, while a slower, extended preheat will favour high temperatures for darker roasts.
Conclusion: Why Brew Temperature Matters
Espresso brewing is a precise and highly sensitive process. The temperature of the water plays a pivotal role in the extraction of flavours from the coffee grounds, affecting everything from acidity and bitterness to sweetness and mouthfeel. By fine-tuning your brew temperature, you can control how different flavours are extracted, ensuring that your espresso hits the perfect balance.
Whether you’re brewing a light and fruity espresso or a dark, rich shot, the ideal temperature will help you unlock the full potential of the coffee. The insulated brew chamber of the Brua3 Max could make all the difference in the quality and complexity of your espresso, bringing you one step closer to the perfect shot!
