Background and Aims Concrete egg fermenters are of increasing interest to winemakers interested in expanding the range of sensory properties that emerge during fermentation. Winemakers and concrete egg fermenter vendors have made a priori assumptions about the liquid mixing efficacy and heat transfer in egg fermenters, which have not been explored in the literature. These assumptions were therefore examined using a computational fluid dynamics approach, along with a model for fermentation dynamics, to compare a concrete egg fermenter with a jacketed cylindrical tank typically used for winemaking. Methods and Results The liquid temperature, external concrete surface temperature and sugar concentration in a concrete egg fermenter were monitored, and compared with values predicted from a reactor engineering model designed to simulate the fermentation dynamics of a concrete egg fermenter, to good agreement. Simulated mixing and temperature control were then compared in concrete eggs and cylindrical tanks. Finally, the impact of wall thickness and air velocity on fermentation dynamics was explored, with both variables found to have a significant impact on fermentation temperature and kinetics. Conclusions Superior mixing and temperature control was predicted in the jacketed cylindrical tank with the concrete shell found to function more as an insulator than a heat sink during fermentation. Significance of the Study This work represents the first quantitative exploration of concrete egg fermenters, and in doing so will act as a tool for winemakers interested in using concrete eggs as part of their winemaking practices.

中文翻译：

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预测混凝土鸡蛋发酵罐的发酵动态

背景和目标 有兴趣扩大发酵过程中出现的感官特性范围的酿酒师对混凝土鸡蛋发酵罐越来越感兴趣。酿酒师和混凝土鸡蛋发酵罐供应商已经对鸡蛋发酵罐中的液体混合功效和传热做出了先验假设，但文献中并未对此进行探讨。因此，使用计算流体动力学方法以及发酵动力学模型对这些假设进行了检查，以比较混凝土鸡蛋发酵罐与通常用于酿酒的带夹套圆柱形罐。方法和结果 监测混凝土鸡蛋发酵罐中的液体温度、混凝土外表面温度和糖浓度，并与设计用于模拟混凝土鸡蛋发酵罐发酵动力学的反应器工程模型预测的值进行比较，以达到良好的一致性。然后在混凝土蛋和圆柱形罐中比较模拟混合和温度控制。最后，研究了壁厚和空气速度对发酵动力学的影响，发现这两个变量对发酵温度和动力学都有显着影响。结论 在带夹套的圆柱形罐中预测了出色的混合和温度控制，发现混凝土外壳在发酵过程中更像是绝缘体而不是散热器。研究意义 这项工作代表了混凝土鸡蛋发酵罐的首次定量探索，