What would likely occur if espresso is brewed with too hot water?

Brewing espresso with water that is too hot can lead to a flavor profile that is burnt and overly extracted. When water temperature exceeds the optimal range, it can cause excessive extraction of the coffee solubles. This means that not only the desirable flavors are extracted, but also the bitter compounds that can contribute to an unpleasant taste. These compounds often lead to a burnt flavor, as high temperatures can scorch the coffee grounds during brewing, resulting in a harsh and unbalanced cup.

The other options do not adequately capture the consequence of using excessively hot water. A weak flavor, for example, is typically a result of under-extraction, which occurs when insufficient flavors are drawn from the coffee grounds, often due to lower temperatures or too short of an extraction time. The formation of crema is influenced by the coffee oils and gases that are released during brewing but is not directly hindered by high water temperature. Additionally, while increased water temperature can speed up extraction time to some extent, the overwhelming effect is usually one of over-extraction and unfavorable flavor characteristics.