Arstechnica Article

By Yun Xie | Published: November 25, 2008 - 01:36PM CT

Used coffee grounds may be garbage to most of us but, to chemical engineers at University of Nevada, they are a versatile source of green energy. Narasimharao Kondamudi, Susanta Mohapatra, and Mano Misra proposed that the solid waste from coffee brewing can do a lot more than act as compost for gardens. They set out to see if they could extract oils from old coffee grounds and chemically convert those oils to biodiesel.

Image Credit: Ragesoss. 

Spent coffee grounds are about 15 percent oil, which is only slightly less than many of the other biodiesel feedstocks. Since the world produces over 16 billion pounds of coffee per year, there is a constant and cheap supply of solid coffee waste. Kondamudi, Mohapatra, and Misra also predict that biodiesel from coffee grounds would be more stable than those from other sources because coffee contains antioxidants that would slow down degradation.

The researchers extracted oils from Starbuck's spent coffee grounds, and went on to perform a standard transesterification process to convert the oil to biodiesel using methanol (a type of alcohol) and potassium hydroxide (a base for catalyzing the reaction). They were able to convert 100 percent of the oil in the grounds into biodiesel; both the extracted oil and biodiesel were stable for more than a month, which is sufficient for industrial applications.

Ground Coffee. 

After the oil is extracted, the grounds can still be used for compost or fuel pellets. The authors estimated that, if spent grounds were converted into biodiesel and fuel pellets in the U.S., it’s possible to make about $8 million in profit per year. On a worldwide scale, based on the amount of coffee that is used, 340 million gallons of biodiesel can be produced from spent grounds.

The authors showed that used coffee grounds are much more than a waste product and can be a source of green energy. Of course, to know if this process is truly green, every step of the conversion would need to be analyzed in detail, but the initial results are promising, especially given that the waste products from the process can be used further as compost or fuel pellets.

Journal of Agricultural and Food Chemistry, 2008. DOI: 10.1021/jf802487s

I found this awesome article on the coffeegeek web site that I thought a lot of people would be interested in.

Author: Mark Prince
Posted: May 21, 2008

You may have never heard of siphon coffee making. Then again, you may have read about it in the New York Times and thought it was some $20,000 gizmo used by crazy coffee nerds in San Francisco. You may have heard of it under a plethora of other names - vacpots, vacuum brewed coffee, siphon brewer, siphon vacuum coffee, and all sorts of word combinations.

This brewing method fell out of favour in the US and Canada by the 1960s, and with only a few holdovers making devices for the next few decades. Most of the major brands that used to make siphon coffee makers eased them out of production during that time, including General Electric, Silex, Sunbeam, Cory and others. Still, the brewing method maintained a hard core set of fans, maybe just in the hundreds, or dozens, and a few manufacturers continued to produce them: Bodum has continuously made a siphon coffee maker since the 1970s. Cona, out of the UK, has been making them since before World War II. Nicro, a commercial small appliances maker, was manufacturing them right up through the 1970s when demand finally disappeared, at least for cafes and restaurants.

In the late 1990s, a bunch of coffee nerds started talking up the joys of siphon coffee makers, or "vacpots", in places like alt.coffee and with the aid of rudimentary photos and pretty basic short video clips, a new (albeit small) generation of people cottoned on to this brewing method, if not for anything else than the show it provided.

And now, well into the first decade of the 21rst century, and some 160 years after the siphon coffee maker was first invented in France and Germany, the technique is set to explode (figuratively, not literally) with almost everyone in the specialty industry taking interest. Peter Guiliano, the famed green bean buyer for Counter Culture Coffee and acknowledged as one of the best cuppers in the business today, lists the siphon coffee method as one of his favourite ways to make coffee.

Back in 1998, I saw my first ever siphon coffee maker in action. I make no joke about this - it was a seminal moment for me in coffee. I was very much into all things espresso at the time, and I still recall the first time I brewed a cup. I'd been reading about vacpots for a few years - mostly in the newsgroup alt.coffee, but also in books like Ken Davids' Joy of Coffee - but it wasn't until I stumbled upon a used Bodum Santos in a flea market that I bought one, took it home and set it up for the first brew.

Almost everything about using a vacuum coffee maker is sensory involved: aromas, fragrance, motion, touch, action. Grind the coffee, add it to the top vessel. Add cold (or hot) water to the bottom. Put the bottom on a heat source. Add the top vessel with its attached siphon. Watch. Liquids defy gravity. The brew gurgles, but it's not boiling. Remove from heat source. Watch the coffee move back down, or "south". Watch the bottom vessel's brewed coffee gurgle as air is drawn through the spent grounds to release the built up vacuum. Remove top vessel. Smell. Ahhh. Pour. Taste. More ahhhh.

So much science. So much sensory involvement. So much fun. And the taste... Do it right, and you'll wonder not at the fact that so many specialty industry leaders consider this "the best".

Following on my new found interest in roasting coffee, I started looking for some more tools to assist me in my roasting quest <grin>.  I found a very useful coffee roasting database program, it is freeware so there is no charge and looks to do everything a home roaster could want. 

Can be downloaded free of charge from - LINK

I have been battling with all of the factors which come into play when making an espresso and thought it was about time that I try and put together a formula and open it up for comments.

 All of the factors in the forumla effect the extraction time & flavour of the coffee and it is only by balancing all of these factors that you will get the best out of the coffee. Some of the factors should remain relatively constant controlled by the barista, whilst others are environment based and are subject to almost constant change, the final extraction should however always be around 25 seconds. 

Article courtesy of Mark Prince @ CoffeeGeek.com 

How to Use a Press Pot The ubiquitous press pot. It's everywhere. It's seemingly easy to use, right? Well, yes, but a little understanding of the device, how it works, and maybe a bit about the history of the product will get you using yours better. If you want some of the richest coffee you can get, a press pot can deliver. What may surprise most is that you can also get a relatively clean brew from it as well, if you have the right tools and prep everything correctly.

The Press Pot History

First, a bit of my own history. I wrote an article on this site some time back that I called Why I like Bodum. You see, press pots were my initiation into the world of quality coffee, at least in North America. I have a lot of loyalty and fond memories of this brewing method and the coffee (and situations) it delivered me.

But how about the real history of the Press Pot? How about this question - which came first, the vacpot or the press pot? It might surprise you, but the press pot came later. It is, of course, a much simpler design than a vacuum brewer, but there were problems. In the 1840s, when the vac pot and balance brewers were first introduced, the concept of a press, or plunger brewing system was around, but the technology to make a tight enough fitting filter didn't. Even the first models by Mayer and Delforge in France were met with limited success.

By the early 1900s, the press pot, called a "Cafeolette" starting becoming more popular and was showing up on grocery store shelves. In the 1930s, Melior introduced the first model with a stainless steel filter and a metal body, then soon they introduced a model reminiscent of Bodum's current day "Chambord" line. Why is it reminiscent? Because Bodum bought that design!

In fact, Bodum is probably more responsible for the common day occurrence of the press pot than any other company. In the seventies, they started introducing their whacked out colours in their plastic, metal and glass press pots. In the 1980s, fueled by their profits, they bought lines like Chambord and brought out more classical-look press pots. The rest is, as they say, history.