Guy Talk: spinning some numbers

Guy Hagner continues to inch towards opening his One Guy Brewing Company in Berwick, PA; he's sent some pictures of the progress -- it's amazing the difference a drop ceiling makes. Here's his latest installation of Guy Talk, a kind of short lecture series on stuff you may not have ever thought about beer. Ever think about just how much yeast is in beer?


NUMBERS

Years ago I read a sci-fi novel in which humans encountered a planet populated by only a few hundred different species of life. The contrast was made with the riotous, virtually limitless diversity and sheer quantity of life found on Earth.

Ever since I’ve been interested in these questions: How many different forms of life exist? What is the total population of living organisms on Earth? The numbers are surely staggering. I can’t give a guess as to the answers, except in the area of brewing.

Brewers’ yeast is a single-cell organism. As microscopic life-forms go it is fairly large (most bacteria are an order of magnitude smaller and viruses are another step or 2 down in size) yet their numbers are huge. A brewer will typically add 10 to 20 million yeast cells per milliliter (ml) of wort to start the fermentation.

Think about that: One ml of wort is about one-thirtieth of a US ounce, and begins fermentation with a quantity of yeast equal to the human population of one of the world’s largest cities. Not only that but the yeast will at least triple in population during the fermentation. For ease of calculation let’s call it 50 million yeast cells per ml during the height of fermentation.

So per ounce of fermenting beer there are 1.5 billion yeast cells. To make one 12-ounce bottle of beer it takes more individual yeast organisms than the number of people that have ever lived.

Annual global production of beer is approx. 1.45 billion barrels (1.7 billion hectoliters). I’m assuming the average fermentation time is a week; so in round numbers the barrelage of beer actively fermenting at any given time is 1.45 billion divided by 52 weeks or 28 million barrels.

Bear with me through this step.
28,000,000 barrels times
31 gallons per barrel times
128 ounces per gallon times
1,500,000,000 yeast cells per ounce equals:


166,656,000,000,000,000,000 individual yeast cells.

So the brewing world’s contribution to the total population of earth is about 166 quintillion.

What’s this all mean? I’m not sure, but if anyone wants to take an educated guess as to the total size of Earth’s population I’d like to hear it.

In the sci-fi story all the planet’s organisms were inter-connected in some creepy way. As the space explorers’ ship returned to Earth there were several stowaways intent on assimilating all of Earth’s life. I don’t think they realized the size of the job ahead of them…