Note: new batches will now be shown on a separate post – go to Current Coffees to see them. If this is your first time here, I invite you to read about what we’re doing below. Thanks!
Off-Grid Solar Power and the Limitations of the HPMDU
Since there’s a finite amount of weight we can carry in the HPMDU, and money we have to purchase batteries, we are limiting ourselves to eight 125 amp-hour 12V batteries (at least for now). This relatively small battery bank serves us well with minimal input from solar panels for a couple days, but when it’s full, it’s full. So, what to do when the battery bank is full and the sun is blazing away for several more hours? Use the energy right now, of course!
Forget Traditional Limitations
Traditionally, resistive loads have been considered a no-go for off-grid photovoltaic systems. Resistive loads are those which are basically a controlled short circuit – electric water heaters, toasters, electric heaters, ovens, and other heat-producing electrical appliances. But, what if instead of trying to store all the power and then use it carefully, you made some extra and used it as it was produced?
That’s our approach. When the battery bank is full and the sun is still shining, we break out the smoker/roaster, coffee roaster, or electric pressure cooker and make something with that energy. We “store” solar energy as roasted coffee, baked gluten-free bread, or a stew.
Let’s Roast Coffee!
All that is to say that we will have a limited amount of solar-roasted coffee available for purchase. I have been roasting coffee for more than twelve years using everything from a hot-air popcorn popper to a cast iron pan to various rather expensive micro-roasters. I’ve often sold or bartered coffee and had excellent reviews from people who drank my coffee.
My current setup is the Gene Cafe CBR-101. I have roasted several hundred batches with it and developed a process that consistently produces excellent results given good raw materials (green coffee beans), which I source from Sweet Maria’s.
Sweet Maria’s Is Awesome
Sweet Maria’s does a fantastic job of developing relationships with farmers and co-ops around the globe and paying them a fair price. I feel good about buying from Sweet Maria’s and stand by their focus on direct trade. If you take the time to read this I’m sure you will understand who I am dealing with for my green coffee beans and how thoughtful the entire process is that brings my beans to your cup. There are still people in the world who consider their impact and do what they can to help others.
Great Coffee Is not Cheap Coffee
To that end, I will be extremely clear with my pricing. This coffee is not cheap. This coffee is also not crap. I pay about $7/pound for most green coffee beans including shipping. When roasted, the beans lose about 20% of their weight (mostly through water loss). A 225g batch of green beans comes out of the roaster weighing 180-185g.
That 185g of roasted coffee costs me $3.50 for beans plus wear and tear on the roaster, power (the PV system cost something up front) and opportunity cost – I could have been doing something else, right? I roast in 225g batches. Depending on the roast, the final weight will vary slightly. I’m not interested in counting grams, but rather in making the best possible coffee, one tiny batch at a time, which takes between 13 and 18 minutes.
Mass-produced Price, Handcrafted Quality
I will typically roast one or two batches of each bean. A one-batch roast will cost $9 and a two-batch roast will cost $17. The 12-oz bag you are probably used to buying would be a two-batch roast from me (and represents one pound of green beans that your roaster bought, btw – now you know why coffee comes in 12-ounce bags). The cost is in line with what it costs in Portland or Seattle for coffee roasted in huge gas-fired roasters by interns for mass consumption.
New batches will now be shown on a separate post – go to Current Coffees to see them.