Since rhubarb made it onto the menu, people have been talking about its toxic content. Is raw rhubarb poisonous when it flowers or from June onwards? Find out here what poisonous rhubarb actually is like.
Is rhubarb poisonous due to oxalic acid?
Is rhubarb poisonous? Rhubarb contains oxalic acid, which can be toxic in high doses. However, a 60kg person would have to eat around 36kg of fresh rhubarb to reach a toxic dose. The oxalic acid in rhubarb has no connection to flowering or harvest time.
Oxalic acid – the harmless culprit
In addition to many valuable vitamins and nutrients, rhubarb contains oxalic acid. This substance hinders the body's absorption of iron, which is a concern for small children and people with kidney disease. Oxalic acid also attacks tooth enamel and binds calcium in the organism.
What seems dramatic at first glance is of course only true in high doses and under unusual conditions.
- 100 grams of fresh rhubarb contain 180 to a maximum of 765 milligrams of oxalic acid
- only from 5 grams, i.e. 5000 milligrams, scientists assume that oxalic acid is a toxic dose
If rhubarb is cooked, the proportion of oxalic acid drops again compared to fresh produce. Roughly speaking, a person weighing 60 kilograms would have to eat a whopping 36 kilos of fresh rhubarb to harm themselves.
First harvest with less oxalic acid
The oxalic acid content in rhubarb only builds up slowly over the course of the vegetation phase. The shell is particularly affected by this. As a result, the April harvest only contains a minimal amount of the toxic substance.
It is recommended to carefully peel the stalks at the end of the rhubarb season. Traditionally, there is no harvest after St. John's Day, June 24th. This protects the vitality of the plant and prevents the consumption of contaminated stems.
No influence of the flower on the toxic content
There is a persistent rumor among amateur gardeners that rhubarb should no longer be eaten after flowering. The fact is that the beautiful flowers and the oxalic acid they contain have nothing to do with each other.
- removing rhubarb flowers improves crop yield
- the mother plant invests its energy in developing more poles
Nobody has to miss out on enjoying fresh rhubarb after it has bloomed. It would be a real shame to limit the already short season based on incorrect information.
Tips & Tricks
Enjoy rhubarb with dairy products, such as a light vanilla sauce. The calcium in the milk binds the already very small amount of oxalic acid as insoluble calcium oxalate and excretes it completely.
