Baking Soda + Potatoes = ???

Above are the potatoes used within this experiment (Home Fries)!

Welcome back to my last and final experiment for the semester! :) While skimming through The Science of Good Cooking, I found something that caught my interest. I read about baking soda and potatoes. I always thought baking soda would just be for baking but in this case, it works for hearty cooking as well! I wanted to try one of their recipes and see if it actually worked. They claimed if you add baking soda to boiling water to blanch the potatoes, it will make them crispier!

What’s the science?

Adding just ½ a teaspoon to 10 cups of boiling water helps make the outside of the potato very crisp and brown because “alkaline baking soda triggers a chain reaction that literally unzips the backbone of the pectin molecules (holds the potato cells together) and causes them to fall apart. This requires only enough alkali to raise the pH of the water high enough to start the reaction, after which it becomes self-sustaining” (Science of Good Cooking 247). Once you boil these potato pieces with baking soda, the pectin molecules are broken apart or unzipped and when you put them in the oven, they will start to crisp because that reaction has started already! Interesting right?

My hypothesis: If I add baking soda to boiling water, then it will make the outside of the potato cube crunchier and browner than if I don’t add baking soda to boiling water.

Independent Variable: Baking Soda

Dependent Variable: Crunchiness and Brownness (Scale of 1-10)

How did I keep this controlled?

I baked both batches in the same oven, used all of the same cooking tools, pans, etc., followed the recipe exactly the same way for both batches minus the baking soda for one batch, baked each for the same amount of time, and used the same type of potato.

In an ideal world…

I would have a more scientific way to measure the crunchiness and the brownness. I didn’t have any tools to determine how crunchy or brown the potato cubes were and that is one thing I would change. Also, I would have had someone help me so I could have put both batches in at the exact same time. To further my experiment, I would have doubled the amount of baking soda to see if it would make the potato cubes even crunchier and browner.

Ingredients Used:

3 ½ pounds of russet potatoes, peeled and cut into cubes

½ tsp baking soda

2 Tbsp. unsalted butter

2 Tbsp. vegetable oil

Steps To Make Home Fries:

1. Preheat oven to 500 degrees F and place rimmed baking sheet on lowest rack

2. Bring 10 cups of water to boil

3. Add potatoes and baking soda

4. Return to boil and cook for 1 minute

5. Drain potatoes and return potatoes to low heat in pot

6.  Shake pot frequently for 2 minutes and until the surface moisture is evaporated

7.   Add butter and 1 ½ tsp of salt after removing from heat

8.   Stir with spatula until there is a thick starchy paste coating (about 30 seconds)

9.   Remove preheated baking sheet from oven and drizzle with 2 Tbsp. of oil

10.   Transfer the potatoes from the pot to the pan (even layer)

11.   Roast for 15 minutes

12.   Remove from oven and flip over the cubes

13.   Place back in oven for 15 minutes

14.   Remove and let cool

15.   Enjoy!

(Ingredients and steps were used from The Science of Good Cooking book.

What happened?!

Below shows a picture of the finished product. The pan on the right are the potatoes without baking soda water and the pan on the left are the potatoes with baking soda water. They look similar in this picture, but in person they did have a difference!

Below is a picture of the 10 pieces I used! the ones on the left are the potatoes without baking soda water and the ones on the right are the potatoes with the baking soda water. Here you can see quite a difference! 

                                                    

Potato Cube	Baking Soda (crunchiness)	No Baking Soda (crunchiness)	Baking Soda (brownness)	No Baking Soda (brownness)
1	10	2	10	3
2	8	5	8	6
3	10	10	10	10
4	3	4	4	4
5	3	6	5	7
6	4	2	5	3
7	7	2	8	3
8	9	4	9	5
9	8	5	9	6
10	8	4	9	5

The average crunchiness for the baking soda cubes was 7. The average brownness for the baking soda cubes was 7.7. The average crunchiness for the non-baking soda cubes was 4.4 The average brownness for the non-baking soda cubes was 5.2. Overall, the baking soda cubes were crunchier and browner. My hypothesis was supported. Yet, as you could see in the picture above, the non-baking soda cubes did get a good brown around them! They were not nearly as crunchy as the baking soda cubes though. This makes complete sense because the alkaline within the baking soda broke down the pectin, allowing the outside of the cubes to get more heat and turn crunchy while the potato cubes without the baking soda had a harder time of getting that heat! 

The take home lesson is this: use baking soda when trying to make potatoes crispy! It really works! :)