Mr. Belvedere Goes to Science Class

December 12, 2007 4:15 pm Published by

Mr. BelvedereOf late there has been some interest in the topic of Science!  And what better science to discuss than that related to our favorite topic: BEER!

Recently Dr. Ellen, PhD entered a post about the head on beer.   At first I considered Dr. Ellen Gives Good Head as the title of this post.  But upon further reflection, this title seemed crass and much below my patrician upbringing.  Since this topic is near and dear to our hearts, I decided to take a moment to offer our humble readers more information on the subject of all things beer…

Beer is a complex, heterogenious fluid and owes its origins to the Egyptians who discovered it quite by accident somewhere around 3100 to 3500 BCE.  To be sure, those early, intrepid Egyptians would be fast friends of this lot as beer was most likely discovered by laziness and an ensuing dare!

According to Charlie Papzian, former nuclear engineer and author of the unoffical homebrewer’s bible The New Complete Joy of Homebrewing, beer was most likely discovered by a lazy Egyptian harvester, who gathered grains in a vessel and left them outside.  At some point, it rained a bit and the grains began to germinate, the water in the vessel evaporated and the growing grain sprouts dried out (this cycle of germination and drying is now called “malting”).  This “Malted” grain now had the sugars maltose and dextrose present.  When the vessel containing this grain again filled with rain water, these soluable sugars were extracted by the water and held in suspension.

Now we owe a bit of the rest to our good friend, Mr. Yeast.  Mr. Yeast presumably was being carried about on the prevailing winds in the area then known as “the Fertile Crescent” around the Nile Delta and was deposited in the aforementioned vessle.  Mr. Yeast was quite happy to go about dining on this sugary concoction left in the vessel by the Egyptian Harvester.  Mr. Yeast realized that he had far too much to eat at this varitable banquet, so he quickly went about making copies of himself through binary fission (alas, there’s no romance story here…And Mr. Yeast could just as easily have been Mrs. Yeast [They don’t really have genetalia, you see]).  Now that there was a whole yeast clan…or “tribe” to keep things of the period, they quickly went to work eating all the sugar they could with the help of Mrs. Alpha and Mr. Beta Amalase-Enzyme.  The Yeasts and the Amalase-Enzymes worked themselves into a literal lather, and went about eating up all the sugars they could find….all the while expelling carbon dioxide gas and ethyl alcohol(yes, yeast farts too).

At some point this lazy egyptian harvester, we’ll call him “Noggin,” had his good buddy who we will call “Carl” over to his hut, presumably to help fix some of the straw-brick damaged in the spring Nile floods and to throw camel feces at passers by.  “Carl,” ever the astute observer, asked (translation provided):
Hey, Noggin? What’s that stuff in the vessel?(Hey, Noggin?  What’s that stuff in the vessel?)
Noggin:I dunno.  I had some grain in there, but I kinda forgot about it.(I dunno. I had some grain in there, but I kinda forgot about it.)
Carl:Dude, I dare you to drink it!(Dude, I dare you to drink it!)
Noggin:No way man, last time I took that bet I didn’t shit right for a week.(No way man, last time I took that bet I didn’t shit right for a week.)
Carl:Okay.  I’ll tell you what, I’ll drink it, but you have to cover my shift next week carving heiroglyphs in the pharos tomb.(Okay. I’ll tell you what, I’ll drink it, but you have to cover my shift next week carving heiroglyphs in the pharos tomb.)
Noggin:Dude!  That’s a fucking deal!(Dude! That’s a fucking deal!)

At some point, “Carl” woke up and reported having mystical visions and an extremely elevated spirit.  This “spirit water” became a big hit and soon enough all the kids were drinking it.

So now we’ll fast-forward about five millenia or so the the present day and the subject of head on beer.  While an “unclean” glass (not Kosher) will in some instances cause a head to form on beer, it is actually the process of nucleation (assisted and unassisted) that causes the formation of bubbles within the glass of beer.  The nucleation is the same basic process that allows the formation of crystals in a solution.

As we mentioned before, beer is a complex fluid and contains many organic compounds disolved within.  When beer is poured into a glass (Kosher or non) the fluid dynamics cause some of the dissolved carbon dioxide (from the yeast farts) to form bubbles through the process of nucleation, usually along the organic compounds suspended within the beer.  As more molecules of carbon dioxide accrete along the nucleation site, they become positively buoyant and float to the top of the glass.  If the bubble has had enough opportunity to gather additional organic compounds, the bubble – along with many other glorious bubble friends – will be suspended at the top of the glass in a wonderful layer of froth commonly refered to as “head.”

Now, as noted before, nucleation is also the process by which crystals may form in a solution.  Assisted Nucleation is the process by which nucleation occurs along a foreign substance – sometimes refered to as a seed crystal.

Much the same process may occur in your average glass of beer.  Take, for instance, the introduction of table salt, or sand into the fluid.  These foreign compounds have sufficient surface area to cause nucleation of carbon dioxide and accretion into larger bubles that will float the the top of the glass, and given the type of beer, ultimately form a “head.”  An untested but probable candidate for assisted nucleation is Mint Mentos.

Athough certain forms of bacteria may cause nucleation, there are many more strains of bacteria that are likely to destroy the “head” formed on beer.  This is due to the properties of bacteria to synthesize enzymes to turn substances into molecules the bacteria can ingest.  Many of these compounds have a catalytic effect and will actually destroy the surface tension of our lovely organic-coated carbon dioxied bubles and render the beer “headless.”

But don’t take my word for it!  Go out and test this hypothesis yourself!  Just stop into your local watering hole today (or on your lunch break) and ask for a pint of your favourite bitter – or “Light” for you Yanks.  Better yet, repeat the experiment two or three times before returning to work as you are likely to experience the same spiritual enlightenment as our explorer Carl from the narrative and it is guaranteed to make your workday afternoon much more pleasant!

Well, I hope you have enjoyed my journal entry.  If you have any suggestions for future journal entries, please contact me at

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