Your step-by-step guide to the perfect sandwich

29 May 2012 by Pete Etchells, posted in Uncategorized

I’m an avid eater of sandwiches – some might say I’m a connoisseur. If you blindfold me and give me a tuna mayo on white and a ham on brown, and I’ll tell you the difference straight away. If only You Bet was still on television.

So, you’ll believe me when I say that I was absolutely ecstatic, chuffed, relieved, verb, when I found out that scientists – sorry, ‘boffins’ – have found the formula for making a perfect sandwich:

"It just looks like a mathematics nightmare to us, but we are assured this set of squiggles is the holy grail to making the perfect sandwich.

In principle, this formula will also describe the butter seeping into the bread, particularly as it warms up because D can depend upon temperature.

{(∂v(x,t))/∂t+ v(x,t)∇.v(x,t)}= ∇p(x,t)+ μ∇^2 v(x,t)+ g

At the interfaces we have a physical and chemical reaction of absorption. The reaction rates depends upon the concentration in the air and the activation energy, Ea, and the area exposed to the air."

How cool is that? Now, that equation looks a little complicated, so in the interests of science, I felt compelled to test it out. That, and I really wanted to know what the perfect sandwich is.


{(∂v(x,t))/∂t+ v(x,t)∇.v(x,t)}= ∇p(x,t)+ μ∇^2 v(x,t)+ g

Hmm. Er, okay, I think I need to start with bread – I guess one of those terms must mean ‘get bread’. Maybe the ‘g’. I don’t know.



Okay, I’m lost. Thankfully, the press release has an outline of the process in a much easier-to-understand way.

“Pressure: Don’t apply unnecessary pressure (the p(x,t) term) it squeezes out the water.”

Got it. No pressure.


No exams for you this summer, Mr Sammich! But the coursework deadlines still apply. Firm but fair, I think.


Back to the boffins on this one:
“Freshness: The equations describe the deterioration with time due to slow diffusion of the moisture, so eat your sandwich while it is fresh.”

But I’ve not made it yet! Okay, I guess I’ll leave this until the end. Note to self: eat sandwich as soon as it is made.


“Butter: Use a thick layer of butter, it is hydrophobic and keeps moisture away from the bread.”

Now we’re getting somewhere.

sammich3-right copy.jpg

Thick layer of butter, tick. Next!

"Moisture: Control the loss, or uptake, of moisture from the air into the bread:

1. Butter protects the top."

More butter? Well, okay…

sammich4-right copy.jpg

“2. Crusts are good; they stop the edges drying out (φair < φbread) or going soggy (φbread < φair).”

Well, I do like crusts. This seems to be getting silly now though…

sammich5-right copy.jpg

“3. Wrap the sandwich tightly to keep air away from the underneath – but don’t squeeze it of course.”

Okay, I tried my best on this one, but if you’ve ever got a present from me, you know what I’m like with wrapping things, so I apologise if it’s not very good. Anyway, wrapped tightly, check. I didn’t know what the equation meant, so I went with wrapping paper, is that right?

Sammich6-right copy.jpg


“Temperature: Most equations are temperature dependent particularly viscosity and absorption rates, keep it cool to reduce the reaction rates.”

Keep it cool, got it.

sammich7-right copy.jpg


“Bread: Use the right bread, a thicker slice has a greater resistance to dampness and can’t dry out so quickly either.”

Why wasn’t this step 1?! I’ve used completely the wrong bread! So close, yet so far. Oh well, it may not be the perfect sandwich, but I guess it’s pretty close:


So there you have it, the formula for a perfect sandwich, in 7 easy steps. I must admit, my hopes are slightly dashed – I had hoped for some sort of filling, like tuna mayo with popping candy, or unicorn spam, or something. But I’m not an expert in these matters, so what do I know?

No, I’ve not actually lost my mind. I intended to write a thoughtful post about how this type of churnalism makes us all look bad – scientists and journalists alike. I just didn’t know where to start. For a less silly commentary on the ridiculousness of “Scientists find a perfect formula for X”-type articles, see my old blog here, or Ben Goldacre’s column about Blue Monday here. In the meantime, scientists, next time someone asks you to be a boffin for a seasonal formula, try and maintain some self-respect and say no, ok?

5 Responses to “Your step-by-step guide to the perfect sandwich”

  1. FirstThunder Tang Reply | Permalink

    ew~~it looks disgusting ~ but the taste maybe will be nice~

  2. Mike Fowler Reply | Permalink

    Still don’t think it would be the worst sarnie I’ve ever tasted. Good job actually testing the theory as well!

  3. Bob O'Hara Reply | Permalink

    No wonder it’s a crap sandwich – you screwed up in Stage 6. Give it some shades, man!

    Perhaps not as the filling, though.

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