BY A.J. HOGG
Daily Science Writer
Published February 7, 2006
Your drinking habit could be ruining the environment.
Todd and Scott Leopold aim to help. They designed and operate Leopold Brothers, a sustainable brewery and distillery that embraces the environmental trinity of reduce, reuse and recycle, while producing a tasty glass of beer or spirits.
In 1995, the Leopold brothers started raising money for an environmentally sustainable brewery and distillery, which they finally opened on South Main Street in 1999. Todd Leopold, brew- and still-master for the brewery, trained in a Chicago brew school, interned in four German breweries, and has been to distilling school in Lexington, Ky. Scott Leopold, an environmental engineer, was crucial in the design stages, creating, as he puts it, "as near a zero-pollution factory as you can get."
The brothers, originally from Colorado, chose to relocate to Michigan because they thought Ann Arbor would embrace the environmental sustainability.
A glance around the brewery shows how tightly they stuck to their goal. Reused steam pipes hold up tables made from lumberyard scrap. There are no coasters waiting to clutter up landfills after only one use, and the bar is built from used doors. They don't have any CFCs - gases used in heating and cooling systems in the past that can destroy ozone in the stratosphere - in their heating/cooling system, which uses a cloth heating duct that distributes heat through seams and the fabric itself. When the heating system kicks on, the cloth duct fills up with air like a room-length balloon, as opposed to a conventional heating duct, which releases heat in one portion of a room.
The efficiencies are also built into the brewing and distilling processes. "Typical beer uses 10 glasses of waste water per beer - we've lowered it to just over one," Scott Leopold said. Hot water is saved and reused in the production processes. The Leopold brothers' brewing vats are so well-insulated that they can maintain temperatures much longer than other breweries.
"People laughed at us for spending so much on insulation," Todd Leopold said.
But during a power outage in 2003, the investment spoke for itself.
"Most breweries had to toss beer," he said.
The Leopold Brothers didn't, even after four days.
Because the beer is produced in Ann Arbor, no fossil fuels are burned to transport it to local mouths. This means less carbon dioxide is emitted to the atmosphere, which might help mitigate climate change.
Between 1860 and 1918, you could walk to a handful of breweries in Ann Arbor and get a locally brewed beer. However, once Prohibition started in 1918, nearly every Ann Arbor brewer went under. Only one company, the Ann Arbor Brewing Company, survived until Prohibition was repealed in 1933. It shut its doors in 1949. Until the rise of microbreweries in 1995, every beer bought in Ann Arbor had to be shipped into town. Now, Leopold Brothers is one of a handful of local breweries, and the only local distiller.
The brewing process
The brewing and distilling equipment is stashed a few feet through a door tucked around a corner of the bar. Bags of malt and hops, the resinous flower of a viney plant, lie on the floor, and catwalks top the steps to the vats.
The 90 keg fermenters and 60 keg vats shiny steel line the walls, and you can walk alongside the brewing process, following the transfer pipes from start to finish. A single computer controls the process, and the entire operation is run by two people.
Brewing is a skill humans have been perfecting for 8,000 years, when it was born in Babylon.
First, the barley malt is soaked in hot water, in a vat called a mash tun. This process, called mashing, revives the barley seeds, "fooling it into thinking its in the ground," Todd Leopold said. This activates the enzymes in the barley malt that converts the starch stored in the seed into sugars, creating a wort - a sweet brown liquid. This time spent in the mash tun determines the body of the beer.
The Leopolds invested in the most efficient brewing equipment available. In this step, typical brewing equipment can extract 70 to 80 percent of the sugars from the malt - Leopold Brothers' equipment can get 96 percent. Not only is this a more efficient use of raw material, but it means they need less malt shipped to the brewery. The less malt shipped, the less transportation is necessary, which burns less fossil fuel. Using less fossil fuel produces less carbon dioxide, which reduces the amount of green house gases released.
In the next step, hops are added to the wort, and the mixture is boiled. The art here, says Todd Leopold, is "balancing the sweetness of malt with the bitterness of hops." This step concentrates the wort, kills any stray microbes, and stops the malt enzymes from converting any more starch to sugars.
After boiling, the wort is transferred to the fermentation tanks, and the leftover malt husks are transferred into a bin. Instead of discarding this used material, "when it's done, the leftover is given to a local organic farmer. The chickens love it," Todd Leopold said. Egg production at this farm increased once they switched to using the malt residue for feed.
In the fermentation vat, yeast is added. As it grows, the yeast converts sugars to alcohol. Before fermentation, the wort is about 14 percent sugar. The yeast activity reduces this to 2 percent for a dry beer, 4 percent for a thicker beer, and the alcohol content rises.
When the beer is removed for conditioning, the conical shaped fermentation vat collects yeast at the bottom of the cone. It is then reused for another batch of beer.
The distillation process
On the other side of the room, the distillation column is clearly the darling of still-master Todd Leopold's eye. Leopold's German still is custom-made. The bottom pot is a sphere about five-feet in diameter, hammered from copper with hand-held hammers. Extending upward from the sphere is a three-foot diameter copper cylinder, with multiple levels of plates and plugs that control which part of the evaporated vapors make it out of the top of the still.
Depending on what is put in the still (the starting liquid, or wash, is usually 6 to 11 percent ethanol), and how the plates and plugs are set, "I'm able to make damn near anything," Todd Leopold said.
And he does. From this one still, they regularly produce gin and vodka, and have bourbon and pisco, a South American brandy, in the works.
The distillation process is based on the fact that different compounds evaporate at different temperatures. This means that by controlling the temperature of the boil, you can control the order in which compounds evaporate, based on their boiling points. A coil of tubing condenses the vapors at the top of the still, returning them to the liquid state, where they are collected. Once it has been heated, the cooling water goes to the hot water recovery tank.
The first compounds to condense off the still are called the heads. These are oily and dangerous compounds that are discarded. One, methanol, is the bane of bathtub booze-makers, and causes blindness. The next set is called the heart. This is what the still-master wants - the ethanol and other really tasty stuff.
The final portion, the tails, is also discarded. It's not dangerous, but it doesn't taste very good, though it can contribute to the final product's flavor.
This is where the art of distilling comes into play. Where do you stop keeping the heart, and start discarding the tails? Only experience tells. As Todd Leopold puts it, "where you put that cut point affects your product."
It sounds simple, but the way the Leopold brothers make their gin is more complicated. Since the flavoring in gin is a combination of botanicals (herbs, spices, or fruits), you can either toss all your flavors in at once and distill gin from the mix, or, as Leopold does, you can distill each botanical alone, then combine them and distill gin from this final mixture of botanicals.
Distilling the botanicals separately (remember, different compounds boil at different temperatures), results in a purer distillation of each botanical. And while some of the botanicals are easy to work with - like cardamon, orris root, or juniper berries - others are a bit labor intensive.
For their orange botanical, the brothers zest crates of Valencia oranges with a hand zester to avoid using the bitter pith.
Right now the gin and vodka are available, and a success.
"We won a silver medal at the international spirits competition in Chicago last September," Todd says.
Pisco, a South American brandy (you may have heard of Pisco sours), is debuting this month. And a Leopold Brothers bourbon is in the works.
It's clear that as dedicated to brewing as he is, Todd Leopold enjoys creating new distilled spirits.
He likes the immediate gratification of making gin and vodka. "For a brewer who's used to waiting 60 days," he gestures toward the 90-keg beer fermentation vats, "it feels like cheating - like using a microwave."
If you want to try their bourbon, you'll have to be more patient than a brewer - it takes at least two years of aging before it becomes drinkable.