Abstract Although there is no indication regarding what type of centrifuge tubes should be used for hop bitterness measurement, this study has demonstrated that the most commonly used tubes (made of polypropylene) can cause a significant deviation in the measured bitterness. The traditional procedure for measuring hop bitterness involves extracting a sample of beer with 2,2,4-trimethylpentane (iso-octane) and measuring the absorbance of the organic phase at 275 nm. This procedure was employed to measure the evolution of bitterness during wort boiling and the mentioned interference was first detected, yielding differences as high as 20% between samples processed in plastic and glass tubes. Then, to elucidate that, an experimental comparison using fourteen samples prepared in glass and twenty in polypropylene tubes, was carried out, employing a classical statistical hypothesis test. The results provided a clear indication (with a 99% level of confidence) that the material of the tube can indeed interfere with the bitterness measurement, which is most likely due to the solubilization of the polymer into the organic phase, once plastic polymers absorb in the ultraviolet range.

中文翻译：

---

聚合物管对啤酒苦味测量的干扰

摘要 虽然没有说明应该使用哪种类型的离心管来测量啤酒花苦味，但这项研究表明，最常用的离心管（由聚丙烯制成）会导致所测量的苦味出现显着偏差。测量啤酒花苦味的传统方法包括用 2,2,4-三甲基戊烷（异辛烷）提取啤酒样品，并在 275 nm 处测量有机相的吸光度。该程序用于测量麦芽汁煮沸过程中苦味的演变，并首先检测到上述干扰，在塑料管和玻璃管中处理的样品之间产生高达 20% 的差异。然后，为了阐明这一点，使用 14 个在玻璃管中制备的样品和 20 个在聚丙烯管中制备的样品进行了实验比较，采用经典的统计假设检验。结果清楚地表明（具有 99% 的置信度），管的材料确实会干扰苦味测量，这很可能是由于聚合物溶解到有机相中，一旦塑料聚合物吸收紫外线范围。