Posted by melissa maples on October 23, 2007

Q: Is it true that one half of an acorn is poisionous, and the other half is safe, and that only animals who eat them know the difference? I've heard this in several different places, but never believed it. I just wondered, and figured someone here would know. Thanks for your time, and for previous answers. They helped a lot. Melissa

State: North Carolina

A: Melissa, I haven't heard about this before but your question really got me to thinking about what this might be referring to. I'm quite sure that there is no truth to acorns being one-half poisonous as you noted but I'm wondering if someone has confused another issue that made them think this was the case?

There are two main groups or kinds of oaks - the white oak group and the red oak group. Those trees in the white oak group produce acorns each and every year (mature trees, that is) growing acorns from flower to seed that ripen and fall to the ground all in that same year. The white oak group's acorns are rather tasty and popular with wildlife, and an important food for Native Americans in precolonial days. The red oak group's trees produce acorns each year too but it takes TWO years for their acorns to ripen (two years from flower to ripened seed). This means that half of the red oak group acorns are ripening on the tree while the other half are still a year away from being ripe. The acorns in the red oak group contain a lot of tannin, a kind of mild acid that tastes yucky, making these acorns less desirable, but still edible, to wildlife and Native Americans. Native Americans learned how to grind up the red oak acorns and remove the excess tannin by pouring boiling water over them and then they were more tasty.

Hope this isn't too long-winded but I'm telling you all of this because I wonder if there are two different possible reasons for this misconception at work here. The first possible reason might be that someone has confused the idea that some kinds of acorns (red oak acorns) not being as good to eat as others (white oak group) simply because of the large amount of tannic acid present? To the best of my knowledge, ALL acorns are edible just as they are, it's just that the white oak acorns are much more tasty. The second possible answer might be that with the red oak group acorns, half of the acorns on these trees are inedible simply because they're not ripe yet while the other half are. Hope this makes sense. Thanks for asking a good question.

John Wiessinger ( October 24, 2007)