Final answer:
Tannins were historically removed from acorns through leaching, which involved soaking and washing the acorns to remove the tannic acid. This process was essential because tannic acid can cause health problems in animals and humans. Similarly, the process of extracting tannins from tree bark like that of the eastern hemlock was used in traditional leather tanning.
Step-by-step explanation:
Traditionally, tannins were removed from acorns by leaching, a process that involves soaking acorns in water to wash out the tannic acid. This was done because tannic acid can be harmful to both animals and humans, potentially leading to conditions such as anorexia, depression, and constipation, among others. To facilitate this, the acorns would often be crushed or ground into a meal and then repeatedly washed with water until the bitter taste was no longer present, a practice which utilized both natural resources and traditional knowledge.
In a similar traditional method, the bark of trees like the eastern hemlock was used to extract tannins for use in the leather tanning process. This highlights the importance of understanding the properties of various plants and their uses in traditional practices.