Beer brewing wastes to energy, Part 1

This last month me and my father brewed our third batch of beer.  The past two batches we brewed were extract beers.  This simply means that the malting, mashing, and sparging process had already been done for us, which makes it a whole lot easier on us just being beginners.  As many of you know who have went through the whole Coors tour and not just the short tour, malting is the process of germinating the grains used to brew the beer.  This is done in a temperature and humidity controlled environment.  Once the grain starts to germinate the process is stopped and then the malted grain is mashed.  Mashing can be thought of as making a giant batch of tea.  The malted grains are first lightly crushed and mixed with hot water.  The hot water extracts the nutrients and sugars from the grain making a sweet sugary "tea".  The grains contain many complex sugars and carbohydrates that much be broken down into smaller and smaller sugars so that the yeast used to brew the beer can utilize them.  Mashing is the process that breaks down these sugars. By just draining off the "tea" many of the sugars stay trapped in the grains, so sparging is utilized to get the remaining sugars out of the grains.  Sparging can be thought of as just rinsing the grains until mostly all of the sugars are extracted.  So after all of that processing you are left with wort, the brewing technical word for the "tea".  For many beginner home brewers all these steps can be skipped by brewing an extract beer.  The extract is just concentrated wort that looks about like molasses.  This extract is mixed with water and the then the beginner home brewer can continue on with the brewing process to make beer.  So this time my father and I decided to step it up and we tried brewing an all grain beer.  An all grain beer is one that is brewed by doing all of the steps talked about earlier, except for malting.  So after we mashed and sparged our malted grains we had nearly 20 pound of spent grain.  This twenty pounds of grain was used to brew just five gallons, can you imagine how much grain is used at Coors.  So what are we to do with all of this spent grain.  I got on the internet and did a Google search and found that people have done many creative things with their spent grains.  One that I thought was very interesting was making dog biscuits.  But anyways after reading about many different ways to use this spent grain, I got to thinking about anaerobic digestion and if energy could be extracted from the spent grains in this way.

Spent Grain Dog Treats!

So after another Google search I found an article in Biomass Magazine that talked about a Germany brewery that has done just this as an demonstration.  The article says that most breweries around the world do already have anaerobic digester to treat their wastewater streams, but this brewery has claimed to be the first to demonstrate that a digester for spent grains can be done.  One big obstacle that digesting the spent grains brings about is that in the past the spent grains have been sold to the agricultural industry as animal feed.  Bringing $9 to $18 a metric ton, digesting spent grain may not always be economical.  The brewery that has implemented this demonstrational anaerobic digestion process says that its been more of a marketing strategy that shows those around them that they can be self sustaining and not use fossil fuel energy.  Convincing the rest of the brewing industry to implement such a technology may be very difficult, but this might just make it possible for home breweries or craft breweries to lead the way!