Just found yourself in a green-blueberries situation, and you’re wondering if the pancakes or muffins are safe for y’all to eat?

Make pancakes or bake muffins frequently enough, and you will eventually encounter one of the great alchemies of nature. As you bite into the pancake or muffin, you can’t help but notice that the once blue-violet blueberries have turned a mystifying dark-green.

This begs the question: What is it that causes the blueberries in your food to turn green? And, when this has happened to the batch of pancakes on your plate or that dozen muffins just out of the oven, are they still safe for you and the family to eat?

Another day, another cooking conundrum. Join us as we explore the facts and come to a scientifically sound answer.

When the blueberries in your pancakes or muffins have turned green, this usually means you added too much baking soda to the batter. They are safe to eat, and you can prevent this from happening again by dispersing the soda more evenly or using baking powder instead.

If you didn’t add any baking soda to the batter whatsoever—and the blueberries in your food nevertheless turned green—you probably prepared the pancakes in a cast iron, carbon steel, or stainless steel skillet, or the muffins in an uncoated aluminum or stainless steel muffin pan.

Now, here’s where it gets even more interesting. Suppose you didn’t add baking soda to your batter, and you used a non-stick pan. And yet, the blueberries still turned green?

In such a case, the most likely the culprit is the tap water that runs in your home.

Most cities, you see, keep their supply of tap water on the alkaline side because overly acidic water causes pipes to rust. Furthermore, your tap water may contain a number of metal ions that seep from the pipes to your tap.

Try using mineral water with a pH level of less than 7 for the better and see if that changes the results. Such water is on the acidic side. If you use it, chances are high that you will no longer have a blueberries-turned-green problem.

Or eat it all up and do nothing at all! When you cook, the ingredients in your food change their color, aroma, flavor, and texture. It’s just that some changes appear to be more dramatic than others.

The Reason Blueberries Turn Green

It comes down to the pigments that make blueberries… er, blue, and the way that these pigments react with the rest of the ingredients in the dessert and with the surface of your cookware when cooked.

Blueberries get their color from the anthocyanins contained in their cells. Anthocyanins are natural pigments with antioxidant properties that give plants their red, blue, or purplish color. Apart from blueberries, they can also be found in tomatoes, blue cabbage, and red onions, to name a few.

According to Very Well Health, anthocyanins have the ability to fight free radicals and reduce inflammation in the body, which turns the fruit and veg that contain them into delicious and nourishing ingredients to add to your home-cooked, lovingly-prepared meals.

These anthocyanins, as American author Harold McGee explains in his 1984 book, On Food and Cooking: The Science and Lore of the Kitchen, dissolve in water, react to pH levels, and denature in the presence of iron ions.

In layman’s terms, the natural pigments that give blueberries their color are quick to seep and dissolve in the cooking water. When mixed with a non-acidic batter (the scientific term being “alkaline batter”) and prepared in a cast iron skillet or uncoated pan, their color will change from blue-violet to green.

How to Prevent Blueberries From Turning Green

The solution to a rather complex problem, as it turns out, is a straightforward one. We have several rules for you that can help you prevent the blueberries in your pancakes and muffins from turning green.

Disperse baking soda evenly in the batter, or substitute with baking powder.

Baking soda contains sodium bicarbonate, an alkaline substance. To produce gas and make the batter bubbly, it must be mixed with an acid, such as citric acid. Baking powder, on the other hand, contains sodium bicarbonate and powdered acid. It’s neither excessively alkaline, nor too acidic.

If, for one reason or another, you truly must use baking soda, and you have no way of substituting it with baking powder, then the best thing to do is to disperse it evenly throughout the batter to ensure that no areas are more alkaline than others.

Make your pancakes on a non-stick or ceramic skillet.

Iron ions react most strongly with the anthocyanins in blueberries, according to a study by researchers at the Department of Food Quality and Safety at China’s Jilin College. Cast iron, carbon steel, and stainless steel pans all contain high levels of iron—and traces of it inevitably end up in your food.

If you use coated cookware, such as a non-stick or ceramic pan, the coating will act as a preventive layer between the vessel and the food, preventing the metal ions from getting to the muffin batter and reacting with the blueberries.

In Conclusion

Nature is the greatest chemist of them all. Whenever we cook, we knowingly or not become its lab clerks. We find great joy in researching and writing about moments such as this, and we hope you found this information helpful.

What’s important is that you can eat those pancakes or muffins free from worry and tell a good story to the folks at the table while you’re at it. Stay well and don’t forget to subscribe!