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Monday, August 15, 2011

Post# 201 - How Many Licks Does it Take to Get to the Center of a Tootsie Pop? A Doctoral Study.

This letter was sent via mail to Tootsie Roll on 9/26/1996 by Herman Letters Staff Member Larry Barnowski:

Dear Tootsie Rollers:

I am a Doctorate Student in the Chemical Engineering field at the University of Michigan. My doctoral dissertation relates to your age-old question:  “How many licks does it take to get to the center of a Tootsie Pop?”  My study encompasses the following factors:
    1) Room Temperature Conditions                  5) Actual Lick Force          
    2) Saliva pH level                                          6) Time Interval Between Licks
    3) “Licking Surface” Area                              7) Flavor of Candy
    4) Coefficient of Friction of Tongue
I have fabricated a “mechanical tongue” that is the absolute average of each of the anthropometric conditions listed above (7.21 saliva pH, 1.32 inch tongue width, 1.44 inch tongue length, 0.12ยต tongue friction coefficient, 21.4 Newton Meter lick force, 2.3 second lick interval).  The tongue fixture is hydraulic in nature, and is hooked up to a computer, that can modify any of the options.  The Tootsie Pop specimen is clamped in a fixture, with a 25 Newton meter clamping force, 1.5 inches below the initial diameter level.  I found, through my tests, that the Cherry Pop offers the  mean in saliva “resistance.”  I use a 72 degree Fahrenheit air temperature, climate controlled laboratory.

I consider our “center” to be the very point when chocolate hits the light of day.  I run my tests on the same hemisphere of the subject until this condition occurs.  A laser beam reflects off of the glossy candy surface, until the beam is absorbed by the less glossy chocolate surface.  When this beam is broken, the center has been reached, and the test is complete.  I read the counter and log the data in my spreadsheet.  I have run 3112 samples to failure.  

I have found the following results:  Maximum Lick Count:  518           
                                                    Average Lick Count:  411
                                                   Minimum Lick Count:  312             
                                                    Process Cpk: 1.75
If you have any questions, please let me know.  I have a few for you.  What constitutes “reaching the center?  Do you count “the center” as being the complete removal of the candy layer, or like me, do you count the first sight of chocolate?  Have you performed any studies?  Under what conditions?  With what results?  Lastly, my supply of specimens has exhausted itself.  Is there any chance of helping out with my research (i.e. freebies)?  It’s all in the name of science.  Thank you for any help you can provide.

All Licked Out,

Larry Barnowski

November 7, 1996

Dear Mr. Barnowski:

It must be a sign of the times--- “How Many Licks does it take to get to the Tootsie Roll center of a Tootsie Pop” has gone high tech.

The commercial asking the “How Many Licks” question aired first in 1968.  It has become a classic and is still airing today.  Over the years, literally thousands of letters have been recorded answering the “How Many Licks” question and the approaches for determining the number have been numerous, varied, and interesting.  Certainly your approach tops them all for precision.

We are sending all flavors of Tootsie Pops to you today for your experiment.  We wish you every success in your search for the answer.

To everyone reporting the number of licks required, we present the “Clean-Stick” award.  Please accept this award for the results you have shown us thus far.

Very truly yours,


Ellen R. Gordon


Note: The letter was enclosed with a case of Tootsie Pops.
This note was sent via mail on 11/14/1996:

Dear Ms. Gordon:

Thank you so much for the delightful package that you delivered via United Parcel Service to my back door.  Your comments were flattering, and the Clean Stick Award is an honor that I have shared with my family, closest friends, and clergy.  Most of all, thanks for the case of Tootsie Pops. 

I have, Ellen, run into a roadblock in my project.  As I place the final touches on the project and prepare for my January 10 dissertation, I cannot help but wonder if the “Crunch Factor” should be calculated into my figures.  As you probably know, the Crunch Factor is the tendency for the subject to become impatient with the slow process of outer shell removal (my lab aides jokingly call it “foreplay”), and chomp right through to the gooey core.  According to my calculations, as performed on a mutually exclusive sample population of 100, varying in age from 6 to 89 years, with the mean age of 34, the Crunch Factor occurs 52 percent of the time.  The average number of licks before crunch (L.B.F.) is 60.  Age appears to have no bearing on this number.

By adding the Crunch Factor, I would be completely changing my arguments, and would require a new approach.  Furthermore, my automated licker cannot be adapted to measure Crunch Factor.  I am pondering the repercussions of standing before my jury and giving my testimony withholding the Crunch Factor.

Whatever I choose to do, please know that your efforts here have been greatly appreciated. 

Keep On Rollin’,

Larry Barnowski
If you go to the Tootsie Roll Site, under FAQ, my results (411 licks) are published, along with two other scientific studies.
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