Synthesis and Solid State Pharmaceutical Centre (SSPC), Bernal Institute, University of Limerick, Limerick, Ireland.
MACSI, Department of Mathematics and Statistics, University of Limerick, Limerick, Ireland.
PLoS One. 2019 Jul 31;14(7):e0219906. doi: 10.1371/journal.pone.0219906. eCollection 2019.
Achieving a uniform extraction of soluble material from a porous matrix is a generic problem in various separation and filtration operations, with applications in the food processing, chemical and pharmaceutical industries. This paper describes models of fluid flow and transport of soluble material within a packed granular bed in the context of coffee extraction. Coffee extraction is described by diffusion of soluble material from particles of one or more representative sizes into fluid flowing through the packed bed. One-dimensional flow models are compared to computational fluid dynamics (CFD) models. A fine and a coarse coffee grind are considered. Model results are compared to experimental data for a packed cylindrical coffee bed and the influence of a change in geometry to a truncated cone is considered. Non-uniform flow in the truncated cone causes significant variation in the local extraction level. Coffee extraction levels during brewing are analysed using extraction maps and the degree of variation is represented on the industry standard coffee brewing control chart. A high variation in extraction yield can be expected to impart bitter flavours into the brew and thus is an important variable to quantify.
从多孔基质中均匀提取可溶性物质是各种分离和过滤操作中的一个普遍问题，在食品加工、化学和制药等行业有广泛的应用。本文描述了在咖啡提取背景下填充颗粒床内流体流动和可溶性物质传输的模型。咖啡提取是通过一个或多个代表性粒径的颗粒中的可溶性物质扩散到流经填充床的流体中来描述的。一维流动模型与计算流体动力学 (CFD) 模型进行了比较。考虑了细磨和粗磨咖啡粉。将模型结果与填充圆柱形咖啡床的实验数据进行了比较，并考虑了几何形状变化为截头圆锥体的影响。在截头圆锥体中，非均匀流动会导致局部提取水平的显著变化。使用提取图分析冲泡过程中的咖啡提取水平，并且在行业标准的咖啡冲泡控制图上表示变化程度。提取产量的高度变化可能会将苦味带入酿造物中，因此是需要量化的重要变量。
