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A Homebrewer’s Corner Feature: Solar Brewing

A Homebrewer’s Corner Feature: Solar Brewing

“Do you have sunglasses?”

“Umm… somewhere…”

“Oh, you’re gonna need sunglasses.”

The scent of fall is in the air — at least for those of us that will it to be — and the bright blue sky overhead is dotted with large puffy white clouds. Mat Falco and I speed up Interstate 95 with the windows open. There is nary a hint of rain or inclement weather. It is, by just about anyone’s account, a beautiful morning.
I look over at Mat, a co-founder of Philly Beer Scene Magazine, and my travel and brewing companion for the day. “You have any idea what solar brewing is?” I ask. He shrugs. “Seems like we got a nice day though.” Indeed.

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“Bad weather for solar brewing.”

I have to squint as I look up at the sky. Billowy white clouds float in an ocean of deep blue. There is a problem, however. The clouds are covering the Sun. In order to successfully achieve the rank of solar brewer, you have to have a perfectly clear sky. This is not that sky. It’s only 10 A.M., and already Joe Bair shows concern.

“I saw, like… it said it was supposed to be nice,” I offer timidly. Joe looks up. “Yeah,” he says, obviously unconvinced. It doesn’t look like the clouds intend on breaking up any time soon. “I’ll show you some things on the internet while we wait.”

Just minutes earlier, Mat and I arrived at Princeton Homebrew. This is Joe’s shop, and above it, is Joe’s home. Princeton Homebrew used to be a storefront in Princeton, NJ. “For some reason, when you’re in Princeton, they think they’ve got you — you won’t leave. Watching your rent go from $800 to $2500 a month in less than 10 years, though… I kept saying I’d move, and I found this place, and I did.” Now Princeton Homebrew calls a five-thousand square foot building in Trenton, NJ its home. It’s a beautiful old building &mash; original crown molding runs the expanse of the ceiling, hand-crafted wood doors adorn the rooms throughout, and it boasts the world’s largest radiator — a black behemoth with over 50 fins. The building’s concrete floor, however, is less than period. A flood several years ago put Joe out of business for over four years, mere months after he and his brewing wares moved in. Joe proudly shows us pictures of the radiant heat flooring he put in to the building over that time, doing almost all of the work himself. As Joe shows us around the building, super-high efficiency and high technology are all around us. “Come on up to the roof” he says. One of us is afraid of heights (I won’t mention who) but we oblige the request and follow Joe upwards.

What we find is somewhat unexpected. Despite the high tech inside the building, this is decidedly low-tech. The roof is black tar, and is covered in a simple, snaking run of high-pressure black tubing. This is Joe’s version of solar heating, minus the solar panels. “Anything that’s black absorbs,” he instructs. The black hose on top of the jet black roof absorbs heat from the Sun, heating the water to well over 120 degrees. Joe feeds this water into his radiant heating system, which works just fine during the winter, he assures us. There is an ulterior motive, of course. Turns out, this system provides a nicely heated 6.5 gallons of water over the 400 feet of 5/8 inch hose — which is about exactly what you’ll need for a full-boil five-gallon brew.

As you may have gathered, Joseph Bair is in every right a bit of a mad scientist. His long grey hair is wispy on top and easily wind-blown. His t-shirt speaks to his previous career in the Princeton University Molecular Biology department. He glows while explaining his mix of low and high technology and how they combine for extreme efficiency. He is driven by what many of us are too lazy to do. A little ingenuity and inventiveness and a lot of black hose has reduced Joe’s heating bill to a mere fraction of the four-thousand dollars a month it was before the flood — and he does it without expensive solar panels. On top of it all, the system provides enough heat to help jump-start home brewing.

Joe’s basic philosophy surrounds the Sun. The Sun’s light creates heat, and black anything absorbs that heat. Proper shading and air flow blocks the heat, and can remove the need for things like air conditioning. Taking that philosophy, he’s built his home and business into a very “green” solar test lab.

As luck would have it, during our tour of Joe’s home-brewed solar heating solution, the clouds have dissipated. The brilliant blue sky has not a single imperfection, and we’re ready to solar-brew. We head off of the roof and back to the tiny parking lot in front of Princeton Homebrew. It’s time to examine the monsters magnifying glasses that met us as we arrived earlier.


When we first arrived, there was not a single parking spot in the tiny parking lot in front of Princeton Homebrew. The parking lot was not filled with cars, mind you — rather, two do-it-yourself hand-built rolling vertical stands, each well in excess of six feet, had been rolled out on to the asphalt. Each stand holds a rotating frame with a large Fresnel lens, which will turn the light of the Sun into a powerful source of heat.

Fresnel lenses work by using tiny concentric rings of perfectly measured angular cuts on one side to take all light that passes through it and redirect it. There are two types of Fresnel lenses — a spot lens, in which all light that passes through is focused on to a single spot, and a linear lens, which creates a focused line of light. Fresnel lenses are expensive — for the size we’re using, they can run over $2000. However, Fresnel lenses were the front screen of every rear-projection big-screen TV for years. Joe simply found some old TVs sitting on the side of the road for disposal, and removed the front screen. “People have no idea what they had in those things,” says Joe.

Fresnel lenses aren’t new. Originally developed in the 1800s, they were most commonly used in lighthouses. The giant, thousand-pound glass lenses that surround the light source in light houses are Fresnel lenses — and their invention was groundbreaking. The light concentrating power of these simplistic lenses changed lighthouses forever. Before they were installed, the light from a lighthouse had a typical visible distance of 1/8 of a mile. After installation, lighthouses were able to throw visible light up to 8 miles.

Originally, they had to be hand-made, with small (or large) pieces of hand-milled glass all blown together. Electronic precision milling eventually led the way to the common plastic flat lens, which is what we’re using today.

To give a quick idea of how powerful the light-concentrating feature of these lenses are, Joe has a “test stick.” A piece of 2×2 inch lumber, the test stick is pock-marked with burn marks. Each lens focuses light to a point in front of the lens called the “focal point.” Joe holds the stick in front of the lens and finds out where it is focusing light. He slowly draws it away from the lens, and the light on the stick grows more and more powerful and blinding. Eventually, he reaches a point a few feet from the lens where pure white light instantly ignites the stick into flames. “That’s the focal point right there.” He tests it a few more times by passing the stick through the focal point. Each time, it ignites into flames within a single second.

Ah. This is why we are going to need sunglasses.

Joe looks over at me with a grin.“They’re hot.” I look back at him, trying to blink away the spots in my field of vision left by the intense white light. “Obviously,” I think to myself. But how hot surprised us even more. The linear lens, which we’re about to use to toast the grain, has a temperature at its focal point of over 800 degrees Fahrenheit. “That’s nothing” Joe tells me. The spot lens, which we’ll focus on the brew kettle to boil the water, can reach temperatures in excess of 2000 degrees Fahrenheit. It’s so hot that when they accidentally passed the focused light over a concrete cinder block, it instantly melted the concrete and left a permanent raised scar in the cinder block. The light hit the cinder block for a total of all of two seconds.

Of course, in order to get those kinds of temperatures, there’s some math involved. The lenses must be aligned with the sun on two axises, and what we’re focusing the light on must be at the lens’s focal point. The power of the concentrated light reduces exponentially as you move away from the focal point. Luckily, the U.S. Department of Commerce’s National Oceanic & Atmospheric Administration (NOAA) research department has a website that shows on Google maps the exact angles of the sun at a particular point on the map. Called the NOAA Solar Calculator, it makes it easy to figure out how to position the lenses for maximum heat generation. Joe zooms the map down to directly over the parking lot. We have our measurements.

During this time, Joe’s assistant brewer for the day, Jim Hammond, has been setting up the lenses and the home-made contraptions that will safely hold our grain and brew kettle under the intense heat of the focused Sun. Jim, a retired tech for the State of New Jersey, is, as far as Mat and I could tell, the happiest man alive. A grey and white mixture of hair compliments the closely clipped white beard on his face. He wears two things of note — the first is an orange shirt from the Red Rock Brewing Company in Salt Lake City, Utah (When Jim and his wife travel, they make it a point to visit local breweries). The other markedly noticeable thing Jim wears the entire time we’re there? A seemingly permanent smile.

The first “contraption” if you will, is a modified wheel chair. The seat has been replaced with a solid slab, and on the slab is a metal bowl with a secondary strainer inside the bowl. This is filled with barley, and the wheelchair is rolled under the focal point of the linear lens until the light hits the grain. Smoke instantly starts to rise from the grain and a wonderful toasted smell fills the air. Occasionally, Jim or Joe stirs the grain to make sure it all gets evenly toasted.

The second of our home-made contraptions is your basic, convenience store glass-front refrigerator. The broken condenser means Joe got it cheap. It is tilted backwards at a 45 degree angle on to a hand truck, and two mirrors are strategically placed on angles inside of the unit. Inside of this a black brew kettle (black — see the correlation?) is placed with a thermometer in the top, and filled with approximately six gallons of water. The metal itself is black — if the kettle were painted black, the paint would instantly burn off.

Once the kettle is inside of the cabinet, the hand truck is rolled under the spot lens. As it passes under the light, a small puff of smoke rises into the air — the light has instantly scarred the rubber seal around the glass door. The cabinet shows the markings of their last solar brew — there are several burn marks in the rubber door surround. We’ll add several more during the course of the day.

Now we wait (and while we do, we open their last solar brew — a pilsner with a decidedly unique flavor of bread and intense citrus). The water in the kettle needs to boil — so we’re waiting for it to reach 212 degrees Fahrenheit. As we wait, the grain cooks and is done. We pass it through a grinder to get it nice and fine. Joe puts the ground grain in to a cheese-cloth like material, and drops the grain in to the kettle to steep. Then, to our surprise, Joe grabs the hops we’ll be using, and puts them in the cooking kettle on the wheel chair. Toasted hops? “It’s experimental, totally” he says. “No one has done this before. We’ll see how it tastes. But wait until you smell them.” As the hops pass under the lens, they instantly begin to smoke — we’ve now come to expect this reaction. However, this is a totally different smell. It’s pungent, piney, and sweet all at the same time. It’s a unique smell I won’t soon forget. But it becomes obvious where the intense citrus flavor in the pilsner came from — Joe cooked the hops last time too. These flavors are indeed unique to beer.

Interestingly, we reach just in to the afternoon, and we begin having serious problems with the brew kettle. It’s simply not reaching temperature. The Sun is almost directly overhead, which means the Fresnel lens needs to be almost completely horizontal. This focuses the light well below the brew kettle, and so we attempt to move the large cabinet into a horizontal position as well. Unfortunately, things are not going well. First, the refrigerator cabinet is too big and these prototype lens stands have not been built to allow the lenses to slide up and down to change the lens focal point. The light that is hitting the kettle isn’t at the optimal focal length, so we’re losing a lot of heat. Secondly, the kettle is laying flat on its side, which means the light that is reaching the kettle is hitting air, not water. The water is no longer heating up. To add insult to injury, the kettle is leaking.

This is the oddest and seemingly most illogical part of this process. Despite the Sun now being it’s most intense, brightest, and hottest, we can’t harness its power. Solar brewing, Joe explains, is actually easier and better in the winter. Mat and I look at each other in disbelief. It goes against all seemingly logical thinking. But because the Sun is always lower on the horizon in the winter, the angles of the Sun are much more optimal. Despite chilly air, the Fresnel lenses can still harness the light from the Sun just fine, and you never reach a point where the Fresnel lens needs to be in a close-to-horizontal position. As I roll it around in my head, it begins to make sense, but who would have figured that out? Well, aside from Joe, of course.

We break for lunch and allow an hour and change to pass. Around 3 pm, the Sun finally retreats back down the sky a little, and Jim has a little stroke of genius. He places the brew kettle under the linear lens instead of the spot lens. While close to 2000 degrees of heat on a singular point in time-space seems optimal, the linear lens delivers a nice constant 800+ degrees of temperature across several inches of space on the kettle. Instantly the temperature begins to rise. Within 15 minutes, we’ve heated the water an additional 100 degrees and reach our boiling point. Hops enter the tank, and we allow the kettle to boil for an hour, while constantly adjusting the lens and cabinet to follow the Sun as it races across the sky.

Success!

An hour later, the hard part is over — and so too is all the fun with extreme solar. We remove the tank from the cabinet, and using a fantastic homemade cooler, we cool the wort as we move it into its fermentation tank. The brew kettle is placed high up on Joe’s truck, and a syphon is attached to the kettle. This enters a coiled copper pipe which has been gently coaxed inside of a garden hose. The wort passes down through the copper pipe as cold water from the garden hose passes over top of the copper pipe in the opposite direction. The wort is quickly cooled to well below 90 degrees during its journey from the brew kettle to the fermentation tank. This is extremely important — 90 degrees is the temperature at which yeast cooks, which would mean dead yeast, and no fermentation.

After all of the wort is syphoned into the fermentation tank, Joe adds yeast and caps the tank with a one-way release valve. Jim and Joe move the tank in to the basement, where it will sit and ferment for just over a week.

Joe and Jim set to cleaning all of the equipment, and Mat and I begin to pack up our stuff. Half of the fun of the day was trying to figure out the optimal settings for the lenses and kettle — once we got that down, the Sun did all the work. We thank Joe and Jim profusely for the experience. It is one of the most unique beer experiences I’ve ever had. During the drive home, Mat and I marvel at what we had just experienced.

It’s amazing what human ingenuity can create. Many home brewers use Propane under their brew kettle to achieve a boil — unfortunately, Propane fuel is one of the worst emitters of greenhouse gasses. What Joe has created uses no fossil fuels at all. The amazing power of the Sun, coupled with a common garden hose and literally 20 seconds of electricity to grind the grain — which, to be honest, could have been done by hand as well — is all the energy we needed. Consider this to be the greenest beer on the face of the planet. When we get home, I tell this same story to many of the people I know. It’s quite simply a marvel of the human mind, and Joe is quite simply a marvel of a brewer.

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