Crema thickness is often discussed, but quantified data is scarce. This review uses a unified observation method to conduct a three-part test of crema thickness, persistence and milk-coffee integration on four beans known for their full body, giving the "crema crowd" a reference data list.

Test setup: the same semi-automatic machine and the same grinder, with unified parameters of 18 g of grounds, 28 seconds, 36 ml; each bean was extracted for three consecutive cups, observing the crema state at 30 seconds, 2 minutes and 5 minutes after the shot, then making one latte each to assess integration. Beans tested: Qianjie Classic Blend (Mamba recipe), Qianjie PWN Indonesia Golden Mandheling, Qianjie Dark Cocoa Blend, Qianjie Autumn Chestnut Blend.

Crema thickness: Golden Mandheling led, with the crema layer visually occupying nearly half the liquid in the cup at extraction, dark brown verging on brown, with a velvety texture; the Mamba recipe followed closely, at about 80% of Golden Mandheling's thickness, one shade lighter in color; the Dark Cocoa Blend and Autumn Chestnut Blend were comparable in thickness, at a solid but not exaggerated level, with a standard tiger-stripe pattern in color.

Persistence: after five minutes, Golden Mandheling's crema was still intact, with only slight dissipation at the edges; the Mamba recipe retained more than 70%; Dark Cocoa and Autumn Chestnut began lightening from the edges at two minutes, with about half remaining at five minutes. The positive correlation between roast darkness and crema persistence was very consistent across the four beans.

Milk-coffee integration is the most valuable dimension. Golden Mandheling's latte has an extremely strong coffee presence; milk cannot suppress its herbal and dark chocolate notes, making it suitable for those who want "a heavy coffee taste," but the latte art pattern color leans dark, and light-colored patterns have average contrast; the Mamba recipe's integration was well-rounded, with crema supporting a full-bodied mouthfeel framework, nutty sweetness and milk's creamy sweetness complementing each other, and latte art pattern clarity was also very good among the four; the Dark Cocoa Blend's latte was like a high-quality low-sugar hot cocoa, with a natural match between cocoa flavor and milk, especially excellent for flavored milk coffees like coconut latte; the Autumn Chestnut Blend's chestnut sweetness noticeably raised the perceived sweetness of the latte, with almost no need to add sugar.

Overall conclusion: for straight espresso or heavy milk coffee, choose Golden Mandheling, whose thickness and flavor intensity are top-tier; for an all-around everyday milk coffee, choose the Mamba recipe, which has no weak points in crema, sweetness or latte art performance; for flavored milk coffee and specialty drinks, choose Dark Cocoa or Autumn Chestnut, whose flavor distinctiveness is a plus in blended scenarios.

The review includes an incidental finding: crema thickness is strongly correlated with bean freshness. In the test, a bag of Mamba recipe opened for two weeks showed about a 30% drop in crema thickness compared with the same product freshly opened. So the data list must come with a usage reminder: no matter how good a thick-crema bean is, it must be finished within its optimal drinking window; stockpiling beans is crema's natural enemy.