Hot coffee bean in a steam on coffee grounds.
Food - Drink
The Reason Dark And Light Roast Coffees Bloom Differently
Blooming a pot of coffee means using a small amount of boiling-hot water to "pre-infuse" ground coffee beans before a full brew. Blooming occurs differently in dark-roasted coffee beans than in light-roasted ones due to bean density and carbon dioxide levels, which ultimately affects the flavor and aroma of your beverage.
Dark-roasted beans harbor considerably more carbon dioxide than lighter roasts due to their extra time in the roaster, making them puffy, brittle, and easier for hot water to penetrate. This creates a more robust bloom with higher effervescence, a heightened aroma, and the potential for more flavor and a smoother texture.
Since light-roast beans spend less time in the roaster, they tend to have harder, denser exteriors that inhibit the release of carbon dioxide. Blooming does occur when you cover them with a small amount of hot water, but the release is generally less potent, and you may need to agitate the beans during the bloom for best results.