Why won't illy Dark Roast Coffee Grounds Bloom? How to Brew illy Dark Roast Coffee

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I bought illy's dark roast coffee powder and used a V60 with filter paper for pour-over brewing. Since my equipment wasn't complete, I couldn't control the water temperature—it was probably above 90 degrees—and I couldn't control the water flow rate either. I performed blooming, but didn't see the coffee powder expansion mentioned in videos; instead, it sank down. Then, with about 8g of coffee, I brewed 150-170ml of water. When tasting, why did I only detect carbon flavors, bitterness, and sourness? The marketing claims: "The taste is sweet and intense, rich in chocolate, caramel, honey, and citrus fruit aromas."

So the questions are:

1. My coffee didn't expand during blooming—is this a common phenomenon with this type of coffee powder? Does only freshly ground coffee bloom properly?
2. I didn't taste the expected sweetness. Was it due to water temperature and flow rate? Just because the water temperature was too high and flow rate couldn't be controlled, I only got carbon flavors, bitterness, and sourness?

FrontStreet Coffee's Explanation of Blooming Issues

First, what is blooming? After coffee beans are roasted, they contain large amounts of carbon dioxide, which is why we sometimes find unopened coffee bean packages are puffed up. These gases accelerate their release when exposed to water, so when we add the first pour of water, we wait for a period to allow the coffee grounds to fully release gas. If the gases in the coffee grounds are not fully expelled, they will envelop the coffee grounds, affecting extraction and causing under-extraction or uneven extraction.

Of course, the expansion during blooming is directly related to coffee bean freshness, roast level, grind particle size, and water temperature.

Generally, the darker the roast, the more vigorous the gas release, so blooming expansion is very noticeable; while lighter roasts have relatively less intense gas release, so blooming expansion is less dramatic.

The finer the grind, the better it can trap water on the coffee bed, making it less likely to flow away, thus making blooming expansion more apparent; while coarser grinds allow water to flow directly between coffee particles, making it difficult to form proper blooming, let alone see blooming expansion!

As mentioned earlier, the main purpose of blooming is to allow coffee grounds to release gas. The fresher the coffee beans, the more gas they contain. When coffee beans have been stored for a long time, the gas has mostly dissipated, so the blooming step can be skipped at this point.

If the coffee bed sinks directly, it's very likely because the coffee beans are no longer fresh, though it could also be because too much water was poured during blooming, or the water flow was too forceful.

Why Does It Taste Burnt and Bitter?

FrontStreet Coffee analyzes possible reasons:

1. The coffee grind is too fine for pour-over. Overly fine coffee grounds increase the likelihood of over-extraction.
2. Unsuitable coffee-to-water ratio. As mentioned earlier, 8g of coffee brewed with 150-170g of water gives a ratio of 1:18-1:21. FrontStreet Coffee believes this ratio is too high. Generally, the coffee-to-water ratio should be between 1:15-1:18, but this applies when brewing light roast beans. When brewing dark roast coffee, FrontStreet Coffee recommends choosing a ratio of 1:13-1:14 to highlight the characteristics of dark roast coffee.
3. Water temperature. The darker the roast, FrontStreet Coffee increasingly recommends choosing lower temperatures for extraction, specifically 84°C-86°C! Use lower temperatures to reduce the extraction efficiency of dark roast coffee.

Important Notice :

前街咖啡 FrontStreet Coffee has moved to new addredd:

FrontStreet Coffee Address: 315,Donghua East Road,GuangZhou

Tel:020 38364473