Overextraction and Underextraction

Brewing great espresso takes an understanding of what actually winds up in the cup when coffee is exposed to water. Roughly 30% of a roasted coffee bean is made of water soluble compounds. 20% of those compounds dissolve fairly easily, while the remaining 10% take a little more work – which is a good thing, because that less- soluble 10% is acidic, bitter, and generally unpleasant. The goal of all coffee making is to extract the easily dissolved oils and compounds while leaving the rest in the grounds.

If ground coffee steeps in water too long, all the soluble compounds will be extracted, which makes for a very bitter brew. This is called overextraction. The opposite of overextraction is underextraction, which occurs when coffee is not exposed to the brew water long enough, leaving the essential flavors and aromas locked in the grounds. Underextraction results in coffee that is weak in taste.

Whether brewed coffee is overextracted, underextracted, or just right depends on several factors, including the ratio of coffee to brew water, the fineness of the grind, the brewing temperature, and the length of time the water is in contact with the coffee. All these factors are either directly or indirectly affected by the barista’s technique.

Before Brewing: The Elements of Great Espresso

Before the espresso machine is even plugged in, you’ll need several elements to produce great coffee.

Fresh Coffee Beans

Great coffee can only come from fresh coffee beans, properly roasted. Many baristas recommend buying beans roasted no darker than a medium roast, the color of which appears as an even chocolate brown. This roast preserves the natural sugars and flavor of the bean, which sets the stage for excellent espresso. A medium roast is the darkest a bean can be roasted without oils developing on the surface.

Darkly roasted beans – which appear dark brown or nearly black – look great, but the extra roasting overwhelms the more delicate coffee flavors and caramelizes any sugars. A heavy “roasted” coffee flavor, often bitter and sharp, will predominate with a dark roast.

To preserve the freshness of coffee beans:

Keep beans in an opaque, air-tight container and store them in a cool, dry place. Refrigeration is not recommended, as condensation tends to form on the beans whenever the container is opened. Freezing can help preserve beans stored for an extended period, but it will also impair flavor.

TECHNIQUES OF A BARISTA

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KitchenAid KPES100 Overextraction and Underextraction, Before Brewing The Elements of Great Espresso, Fresh Coffee Beans
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KPES100 specifications

The KitchenAid KPES100 is a sophisticated kitchen appliance designed for those who appreciate the art of cooking and the efficiency of modern technology. This electric stand mixer combines style, durability, and functionality, making it a staple in any culinary space.

One of the standout features of the KPES100 is its powerful 1.3 horsepower motor, which delivers impressive mixing performance to handle a variety of tasks. This robust motor ensures consistent results whether you're kneading dough, whipping cream, or mixing batter. The mixer comes with multiple speed settings, ranging from gentle stirring to high-speed whipping, giving users flexibility for different recipes and ingredients.

Another key characteristic of the KitchenAid KPES100 is its 4.5-quart stainless steel mixing bowl. The bowl is not only durable but also features a comfortable handle for easy pouring and handling. The bowl’s polished surface is easy to clean, making it a practical choice for any busy kitchen. Additionally, the bowl is dishwasher safe, simplifying the cleanup process after culinary endeavors.

The KPES100 incorporates the Planetary Mixing Action technology, which ensures that the mixing attachment moves in one direction while the bowl rotates in the other. This allows for thorough ingredient incorporation, achieving better mixing results than traditional mixers. This technology is particularly beneficial when working with thick doughs or heavy batters, as it ensures that all ingredients are evenly mixed.

Included with the mixer are several attachments, including a dough hook, a wire whip, and a flat beater, allowing users to tackle a wide range of recipes right out of the box. The easy-to-use attachment system also means that additional accessories can be purchased separately, expanding the mixer’s versatility.

Design-wise, the KPES100 showcases KitchenAid’s signature aesthetic, featuring a sleek and stylish profile available in multiple colors to match any kitchen decor. Its robust construction ensures longevity, while the non-slip feet provide stability during operation.

In summary, the KitchenAid KPES100 stand mixer is a powerful and versatile appliance that combines innovative technology with timeless design. Its efficiency, durability, and range of attachments make it an ideal choice for both novice cooks and seasoned chefs alike, helping to elevate the cooking experience in any home.
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