Engineer fun stuff

Breaking strain of a KitKat – official definition

wrapped kitkatThe question of the day is what is the breaking strain of a KitKat? This came up in conversation in the Strugglers last Friday “early doors”. I don’t recall the context, it was in the pub. In the pub these things have to be written down, or immediately forgotten.

The act of writing things you hear in pubs used to be done on the back of beer mats. Nowadays it’s rattled off in an email addressed to oneself which is what I did in this case. Saves a fortune in beer mats. Extends their useful life. People will no doubt still vandalise beermats, primarily in the execution of the “who threw that beermat” joke whereby a couple of tears are made in one side of the mat which is then affixed to the nostrils. The person stands up and utters “who threw that beermat”. Always gets a laugh. Ish. The how many beermats can you flip game is not described here as it is not destructive to the beermat. I digress.

Continuing with the digression one has to ask oneself how many good jokes heard in pubs have been forgotten because they weren’t immediately written down. How many great ideas have foundered on the beer washed rocks of the tavern, inn or public house?

part opened kitkat

Lots. When I was a student in Bangor I used to occasionally hitch-hike the length of Wales to visit my grandmother who lived in Cefneithin, a small mining community between Llanelli and Caerfyrddin. She had a traditional Welsh approach to meals. A cooked breakfast would be followed by elevenses, lunch at 12, afternoon tea at four and then dinner at 6pm at which point, after a respectable interval I would be kicked out to the pub and return home to a plate of ham sandwiches waiting for me in the kitchen.

4 fingers kitkatOn one such occasion I went to the pub and woke up the next day to find a beermat with the words “parrot” and “coal” written on the back. They were the key points to a great joke I’d heard the night before. Only problem was I couldn’t for the life of me remember the rest of the joke. Ah well.

This doesn’t get us any nearer to answering the question of the day. Before we can answer we have to agree on the unit of crossed kitkatmeasure used to define the breaking strain. If you look up “breaking strain” on Wikipedia you find yourself redirected to a page about Deformation mechanics. I had hoped to come up with a post here that illustrated an intellectual grasp of the necessary physics associated with KitKat breaking strains described in an easily understood way that further showed me as a true man of the people.

Unfortunately having stared at the Wikipedia page for some time my brain began to hurt. I pulled back before the activity got too dangerous. My brain too, like the humble KitKat, has a breaking strain. The units for the breaking strain of my brain are likely to be different to that of the breaking strain of a KitKat. I am unable to describe either for the reasons mentioned above.

In the interest of finishing off this post to our mutual satisfaction it is still necessary to somehow define the breaking strain of said KitKat. A sensible way to do this might be to describe it in terms of thumb pressure. This however brings with it problems.

Experience tells us that a four finger KitKat will be easier to break than a two finger job, assuming that you’re trying to break it along the vertical central line1. This is because the additional width of four fingers over two fingers brings with it twice as much amplification of force due to leverage from the sides of the KitKat.

The breaking strain will therefore vary dependent on the size of the KitKat. We don’t need to worry about that here but in the table below the differences are examined. Laboratory testing (in the pub) has shown that there are distinct grades of thumb pressure:

Thumb pressure Practical use
Very light No effect on a KitKat. Only occasionally applied when a gentle nose scratch is required
Quite light No effect on a KitKat. Used when attempting to turn over a page in a paper or novel, sometimes requiring the application of moisture to the thumb
Lightish Feels as if it should have an effect on four fingers of KitKat but in practice does not. Usually the pressure required to scratch a bit of crud off your phone screen.
Moderately medium This will always break a four finger KitKat and is the standard pressure for such a task. Also works on spaghetti when you are trying to get it all in the pan. Not good enough for two fingers.
Medium Also used in breaking four fingers although borderline overkill for many people. Could work for two fingers in the right environmental conditions. Is usable on Breakaways but why would you?
Strong medium The standard application for two fingers. Not really suitable for four fingers as can cause finger strain when the KitKat breaks unexpectedly easily.
Medium strong As with four fingers in the Medium category this is almost overkill for two fingers. This amount of pressure is almost enough to break a thick slab of Cadbury’s chocolate although we all know this often takes a bit of a smack on the corner of a table to get it going. Also useful for breaking pork scratchings into smaller more manageable pieces.
Strong Overkill for all types of KitKat and should only be used with caution on anything as thumb strain is a real danger. Will definitely work on thick slabs of chocolate. Not many people can exert this amount of thumb pressure. A recognised component of “plumber’s grip”
Uber strong Only reached after completing 7 years plumbing apprenticeship. Very rare.

That’s it as far as KitKats and breaking strains go. Hope this has been of some use. Look out for future posts on quantification of willpower when offered another beer.
broken kitkat

Images courtesy of @TomAndThat – follow him.

1 For the purpose of this exercise we assume that the KitKat is to be broken into two equal halves along the central line. Breaking off one finger with three remaining requires totally different physics. We also assume that the KitKat is not being broken across the middle of all fingers. Ironically to do this for four fingers takes more effort than for two which is the total opposite to the scenario first described.

Other food related posts:

How to cook the perfect baked bean
Best pancake toppings
Important announcement on a Sunday morning

Trefor Davies

By Trefor Davies

Liver of life, father of four, CTO of, writer, poet,

3 replies on “Breaking strain of a KitKat – official definition”

Yes Peter. Problem is we are entering complex territory. As chocolate melts it makes the fingers slippery an can really mess up the table of thumb pressures.

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