Barley, Water, Hops, and Yeast - Part 4

"God is good!"  they exclaimed after tasting the beer, obviously a gift from above.  A few simple ingredients, a few weeks and Hokus Pokus, something amazing.  The water wasn't safe to drink, but this beverage was both safe, tasty, and nutritious.  Like liquid bread.  It made you feel good too!  Praise be to (name your favorite deity)!

Some will say the discovery of beer is a key element in the transition of the human race from hunter-gatherers to a more agrarian lifestyle.  This led to cities, and opportunity for education and learning, etc.  A monumental shift in the human civilization, and it is all because of the discovery of this wonderful substance we call beer.

How did it begin?  No one is quite sure, but it is believed to have been accidentally discovered.  It could have gone something like this.

A Story

Some 10,000 year ago an unknown ancient Sumerian forgot to bring his basket full of barley into the hut (tent, cave, hole in the ground?) one evening after another long day of travel.  It happened to storm that night.  Imagine his mood the next day while having to carry this now very heavy and water soaked package during the journeys of that day.  He probably had a hard time keeping up with everyone else, and I bet they made fun of him due to his lack of conscientiousness the previous evening.  Doesn't everyone know the importance of keeping the grain dry?

On and on they walked that day, and he became most thankful the next stop that evening was a scheduled three day stay.  He pushed through the day, knowing if he worked hard, he'd have time to relax upon arrival.  Later that night when they finally arrived, sore and tired, he was eager to drop the load off his back.  He immediately went in the hut/tent/cave, laid down and was fast asleep.

More rain ensued that night.  The next few days were uneventful, until the day of departure.  That morning, everyone was bustling around and gathered their cargo for the next journey.  Our friend too, went to gather his bundle of grain to find it setting in the basket, which was by now also full of water.  What is that lovely smell?  This water seems different.  Ever curious (and a bit thirsty) our hero decided to drink up.  "It's amazing!  Hey Maris, check this out," he exclaimed and called to his friend.  Soon the entire camp was gathered around this basket, full of this mysterious concoction.  It caused quite a stir.  What magic has happened in your basket?  We must stay here longer and more closely examine the evidence.

Yeast

Of course today, we know the source of that magic.  It is a single celled living organism known as yeast.  Or should we say billions of single cell organism.

Active Fermentation, the yeast krausen at the top.

There are a lot of yeast strains which have been cultivated and used for certain types of beer over the years.  Many breweries will have their own house yeast and will take care to preserve and keep it healthy.  Each type will impart a different set of flavors.  The yeast alone can have a huge impact on the flavor of beer.

We are fortunate today to have access to many various strains of yeast, including historic strains from all over the globe, through companies like Wyeast and White Labs.  With a little effort and know how, yeast from certain bottle conditioned beers can be cultivated and then used for brewing the next batch of beer.

For beer, there are two main types of yeast used.

Saccharomyces cerevisiae - Ale yeast, or "top fermenting"
Saccharomyces Pastorianus - Lager yeast, or "bottom fermenting"

The ale yeast will perform best at higher temperatures, between 60-74 degrees, and the lager yeast works best at temperatures in the 40-55 degree range.

Cultivated yeast, settled in hibernation at the bottom of the jar.

The possibilities and combinations of ingredients in beer really are quite endless.  I've only scratched on the surface here with yeast, but if I go on any longer, I risk you losing interest.  There are a lot of resources out there, including books specifically about yeast.  What is important here is the variety available to brewers and the fact that such a small thing has an enormous impact on beer.  In fact, without the yeast, there is no beer.

Yeast is good.  Yeast is good indeed.

Relevant Links:
Part 1, Barley

Part 2, Water

Part 3: Hops