Consistently yummy: examining the consistency of mashed potatoes

Consistently yummy: examining the consistency of mashed potatoes

Mini-experiment

Background:  It’s all about the starch.  As a soccer player, starch is an important food to be consistently eating throughout the season.  I thought it would be interesting to investigate one of my personal favorite starch-specific recipes, mashed potatoes.   Potatoes are comprised of 16-22% starch, which makes the texture and taste majorly influenced by the starch content of the potato (text, 237).  Starch molecules are very easily manipulated and different creams, stirring techniques, and temperature exposure can change cause molecules to burst changing the texture and taste potential for this dish.  I specifically was interested in the consistency of the potatoes because I have had mashed potatoes that were fluffy and creamy, but I have also had mashed potatoes that were gluey and runny.  I was interested to investigate the causes of each consistency, so I decided to look at the addition of half and half cream compared to sour cream. 

Hypothesis:  Sour cream will make the mashed potatoes thicker and more cohesive to a plate than mashed potatoes made with half and half. 

Null hypothesis: There will be no difference between the cohesiveness to a plate of mashed potatoes made with half and half and sour cream. 

Independent variable: Sour cream or half and half

Dependent variable: time to fall off of plate

I will standardize:

-          Amount of mashed potatoes

o   2 lbs each batch

-          Mashing method

o   Ricer

-          Sour cream/ half and half added

o   1 cup

Results

	Half and half	Sour cream
Time (s)	8.53	11.53
	26.91	44.26
	35.28	58.19
Average	23.57333333	37.99333
Stdev	13.68358993	23.95292
SEM	7.900224329	13.82922

     

The average time for a scoop of mashed potatoes to fall off of a plate when turned upside down was greater for sour cream (M=37.99333) than for half and half (M=23.57333).  

Mashed potatoes with half and half

Mashed potatoes with sour cream

Upside down plate to measure potato consistency

Discussion

Although the sour cream had a higher mean time to fall during the experiment, it was not a significant result.  Without a significant result, the null hypothesis must be accepted.  The standard error of the mean was very high because there was a high variance among data collected.  The mashed potatoes made with sour cream were expected to be thicker, and therefore stay on the plate longer.  This hypothesis was made due to the simple fact that sour cream has a thicker texture than half and half cream.  When the data was being collected, the same scoop of potatoes was used 3 times in a row which might have influenced the cohesiveness because it is clear that the potatoes took longer to fall after each trial.  The experiment was kept mostly consistent in terms of standardizing variables, but the one limitation in standardization came from the plate drop.  When the same scoop was put back onto the drop plate, it still had potato remnants on it which may have influenced the cohesiveness.  For future experimentation, it would be valuable to investigate further methods for data collection in potato consistency, the influence of stirring would also have interesting implications for consistency as starch granules often are crushed in intense stirring which leads to gluey runny results.   


Sources:

Text book

Crosby, G. (2012). The science of good cooking: master 50 simple concepts to enjoy a lifetime of success in the kitchen. Brookline, Massachusetts: America's Test Kitchen.