When brewing pour-over coffee, if the filter basket ends up with a thick, muddy bed of grounds instead of distinct, granular particles, it often means the coffee was ground too fine, which easily leads to over-extraction. When faced with the dilemma of pre-ground coffee that cannot be made coarser, besides switching to immersion extraction, there is another distinctive approach using high concentration and low extraction—the mud flow. It uses extremely fine grinding combined with agitation to rapidly dissolve flavor compounds in a short time, then dilutes with hot water, resulting in coffee with a normal extraction yield and full flavor. In this article, Front Street will explain in detail the principles and specific operating parameters of the mud flow, helping you easily tackle the problem of coffee grounds that are too fine. [more…]