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Could Making Beer From Sewage Save Us From The Drought?

[Photo Credit: Vince C Reyes]

[Photo Credit: Vince C Reyes]

The historic drought in California and other U.S. states challenges us to rethink the way food production and consumption shapes our available water supply. To that end, one adventurous brewing club, The Oregon Brew Crew, collaborated with Oregon’s water utility, Clean Water Services, to brew beer from waste water. This comes as part of the water utility’s initiative to make better use of recycled water. As beer is 95% water, we could potentially save significant volumes of water through this less glamorous route.1

To be clear, the brewers did not make beer straight from water entering out of the toilets and sewers of Oregon. Clean Water Services provided the brewers with “ultrapure water” for making their beer. Ultrapure water is made from water that is purified using the most advanced water treatment methods available. Ultrapure water is not new, but is normally not used for brewing. It is traditionally used for generating water for electronics and pharmaceuticals production, scientific research, or any other application where water must be free from as many contaminants as possible.

To generate ultrapure water, Clean Water Services combines traditional wastewater treatment with more advanced methods. For this process, sewage is first cleaned using traditional wastewater treatment, which includes screening, sedimentation, biological treatment, and disinfection. After this step, the sewage is fit to be released to lakes and rivers, but gets a deeper cleaning through more advanced methods. In the case of the water used by the brewers, Clean Water Services uses a three-step process of Ultrafiltration, Reverse Osmosis, and Enhanced Oxidation to produce their ultrapure water.

The water is first subject to Ultrafiltration and Reverse Osmosis. These processes work like a kitchen sieve as they push water through small pores in a barrier to separate water from different molecules. While both Ultrafiltration and Reverse Osmosis use similar physical separation mechanisms, they vary in the products they can remove from water because of their differing pore sizes. Ultra-filtration can be used to remove particles as small as viruses and bacteria (0.005 – 0.5 μm), while Reverse Osmosis uses finer pores, which can remove even smaller molecules like herbicides, pesticides, salts, and metal ions (0.0001 – 0.001 μm) (Figure 1).

Figure 1: The size of materials that can be removed by Ultrafiltration and Reverse osmosis. Figure Credit: Designerwater.co

Figure 1: The size of materials that can be removed by Ultrafiltration and Reverse osmosis. [Figure Credit: Designerwater.co]

In contrast to Ultrafiltration and Reverse Osmosis, the final step, Enhanced Oxidation, uses chemical methods to eliminate any remaining unwanted products in water. Specifically, Enhanced Oxidation uses ultraviolet (UV) light in combination with chemicals like hydrogen peroxide (H2O2) and ozone (O3) to generate hydroxyl radicals. The high energy from the UV light breaks down chemical bonds to form hydroxyl radicals (·OH). For example, here is the break down of hydrogen peroxide by UV light:

H2O2  + UV -> 2·OH

A hydroxyl radical is just a hydrogen atom bonded to an oxygen atom with an extra electron. Having an extra electron makes hydroxyl radicals very reactive and can break down undesirable molecules in water. This final step removes any remaining contaminants that were not eliminated by Ultrafiltration and Reverse Osmosis.

Figure 2: Ultrapure water (high purity water) compared to river water, cleaned sewage water, and tap water. [Image Credit: huffingtonpost.com]

Figure 2: Ultrapure water (high purity water) compared to river water, cleaned sewage water, and tap water. [Image Credit: huffingtonpost.com]

After these three treatments, the ultrapure water was ready to be used for brewing. In regards to taste, this process produced bland tasting water that results from the absence of minerals and salts that are normally found in water from groundwater, reservoirs, lakes, rivers, and the tap2. These atoms and molecules can be challenging for brewers, as they impart a natural flavor to waters that may not be congruent with the desired beer’s flavor profile3. Instead, when using ultrapure water, the brewers had the freedom to build in whichever flavors they desired. The hops, grains, yeast, and additional spices controlled the beer’s flavor profile rather than the water.

Currently in the U.S., recycled water typically cannot be used directly as drinking water, regardless of how much it is cleaned. Generally, recycled water is only used to water landscape, cool power plants, or flush the toilet. But with growing concerns over shrinking water sources, these views are changing. In 2010, a study by the California State Water Board examined the potential contaminants in recycled water, current water treatment technology, and human health studies of exposure to these contaminants. The conclusion was that recycled water could be safe for human consumption4. These results have been confirmed by other research as well5.

Projects like this may cause you to re-evaluate your bias about the source of your water (and beer). Regardless of the origin of your water, advances in water treatment technologies may enable us to produce safe drinking water from wastewater. But the question still remains: would you feel comfortable raising a glass of beer made from recycled waste water to your lips or would you pour it down the drain?

Learn More

  1. Water and Wasterwaster: Treatment/Volume Reduction ManualBrewers Association.
  2. Is Sewage Beer The Next Big Thing?Huffington Post.
  3. To Grow A Craft Beer Business, The Secret’s In The WaterNPR: The Salt.
  4. Final Report: Monitoring Strategies for Chemicals of Emerging Concern (CECs) in Recycled WaterState Water Resources Control Board.
  5. Rodriguez, C., Buynder, P.V., Lugg, R., Blair, P., Devine, B., Cook, A., Weinstein, P. Indirect Potable Reuse: A Sustainable Water Supply Alternative. International Journal of Environmental Research and Public Health. March 2009; 6(3): 1174-1209.

Vince ReyesAbout the author: Vince C Reyes earned his Ph.D. in Civil Engineering at UCLA. Vince loves to explore the deliciousness of all things edible.

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Bar Stools and Molecules: Buttery Nipple Science

[Photo Credit: Vince C Reyes]

[Photo Credit: Vince C Reyes]

You may think a buttery nipple is just a fun shot to buy a friend on his or her birthday, but it’s more complex than that. It’s got layers… specifically two. For those not familiar with the bar classic, the buttery nipple is composed of a layer of Irish cream sitting on top of butterscotch schnapps.

Buttery Nipple Shot Recipe

½ oz. Irish cream
1 oz. Butterscotch schnapps

  1. Pour 1 oz. of Butterscotch schnapps into a chilled shot glass.
  2. Carefully pour ½ oz. of Irish cream onto the back of a downturned spoon so it rolls from the spoon and floats on the surface of the schnapps.
  3. Enjoy!

This and other layered shots like the American flag, the B-52, and the Alien Brain Hemorrhage, take advantage of the slight differences in density among spirits. As density, a substance’s mass per unit volume (Density = mass / volume), dictates the layering in these drinks; the most dense liquid is placed at the bottom followed by progressively less dense liquids. In the case of the buttery nipple, the less dense Irish cream floats on the more dense butterscotch schnapps. If you were to reverse the order with the butterscotch schnapps poured on the Irish cream, the layers would not form. The more dense butterscotch schnapps would sink to the bottom of the glass and result in a mixture of the two spirits.

For the home bartender looking to make new layered drinks, the absolute density of a spirit is not always easy to measure. However, a different quantity, specific gravity, is often available online1. Specific gravity is the ratio of the density of substance to water (specific gravity = density of a substance / density of water). Water has a specific gravity of 1.0. More dense liquids have specific gravities greater than 1.0 and less dense liquids have specific gravities less than 1.0. In the case of the buttery nipple shot, butterscotch schnapps (Dekyper’s ButterShots) has a specific gravity of 1.12 while Irish cream (Bailey’s) has a specific gravity of 1.06.1 The specific gravity is often available online for alcoholic beverages because it is important in the fermentation and distillation process, and different beers, wines, and spirits have characteristic specific gravities.

If the specific gravity of an alcoholic beverage cannot be found, some recommend using proof or alcohol by volume (ABV) to layer drinks. Both are mandated on all alcoholic beverages sold and therefore easy to find. In general, proof is the amount of alcohol in a beverage. Specifically in the US, proof is defined as twice the percentage of the alcohol by volume. The alcohol in any beverage you drink is ethyl alcohol, also called ethanol (C2H6O).

Figure 1: Molecular Formula of Ethanol [Image Credit: Vince C Reyes]

Figure 1: Molecular Formula of Ethanol [Image Credit: Vince C Reyes]

At room temperature (77°F or 25°C), ethanol has an absolute density of 789.00 kg/m3 and a specific gravity of 0.7872. As many alcoholic spirits are primarily a mixture of ethanol and water, which has an absolute density of 999.97 kg/m3 and specific gravity 1.0, greater alcohol content can often correspond to a smaller density. For example in the case of the buttery nipple, Irish cream (Baily’s) is 17% ABV, while Butterscotch schnapps is 14.8% ABV. Therefore, the higher alcohol content and corresponding lower density of the Baily’s Irish cream allows it to sit on top of butterscotch schnapps. This shortcut, however, is not always correct as many spirits have ingredients other than water and ethanol. Many spirits contain cream, sugars, or other flavoring agents, which can change their densities, making alcohol content an imperfect proxy for density. For example, Smirnoff’s flavored vodkas all have 35% ABV, but have varying specific gravities: citrus vodka has a specific gravity of 0.96, while the more dense watermelon vodka has a specific gravity of 0.981.

Figure 2: Layering in a Buttery Nipple.  *ABV is not always an indicator of density. [Image Credit: Vince C Reyes]

Figure 2: Layering in a Buttery Nipple.
*ABV is not always an indicator of density. [Image Credit: Vince C Reyes]

Lastly although other factors such as altitude affect density, temperature is the other most relevant factor for an aspiring bartender. Liquids are denser when cold. Temperature is an indicator of the speed of molecules within a substance. At low temperatures, liquids have slower moving molecules that pack closer together resulting in greater mass per volume. In contrast, at higher temperatures, molecules in liquids move around more quickly and take up less space resulting in a reduced density. For example, water near room temperature (70°F [21°C]) is less dense (0.998 g/cm3), than water near freezing (1.000 g/cm3 at 39.2 °F [4.0 °C])3. This is why using chilled spirits, glass wear, and spoons when making a layered shot can ensure that spirits remain at their densest and form layers.

Ultimately, a great layered shot is one that is not only effectively layered, but also delicious. If you don’t enjoy the buttery nipple, you now have the scientific knowledge to experiment with your own concoctions!

Learn more

  1. Specific Gravity of Different Spirits from GoodCocktails.com
  2. Specific Gravity of Other Liquids from Engineering Tool Box
  3. The Density of Water at Different Temperatures from the US Geological Survey

Vince ReyesAbout the author: Vince C Reyes earned his Ph.D. in Civil Engineering at UCLA. Vince loves to explore the deliciousness of all things edible.

Read more by Vince Reyes


Beer Crust Apple Pie

The Science of Pie – June 1, 2014
Best Scientific Pie
Christina Cheung, Tori Schmitt, and Elliot Cheung (Team Pretty Intense Pie Enthusiasts)

Adding alcohol to a pie crust is a fairly mainstream way of obtaining a nice flaky shelter for a delicious filling within. Vodka is the go-to spirit for crusts, but other beverages have found their way into the realm of apple pies too. One team at the 2014 Scientific Bake-Off, team P.I.E. (Pretty Intense Pie Enthusiasts), was intrigued by the plethora of alcoholic options available to them for pie crusts, and chose to use their scientific prowess to determine the best choice. Two variables guided their experiment: how do carbonation and alcohol concentration affect the flakiness of a pie crust?

Christina Chung presenting team P.I.E's experiment to the judges (Photo Credits: Patrick Tran)

Christina Chung presenting team P.I.E’s experiment to the judges (Photo Credits: Patrick Tran)

Team P.I.E. began by making six experimental crust doughs, each containing either water, beer, stale beer, diluted vodka, regular vodka, and Perrier. To measure flakiness, a quality difficult to quantify, they compared the average height for each baked pie dough to indicate how much the dough has risen during baking. To account for bubbles, height measurements were taken at the center and edges of the crust.

Elliot Cheung hard at work preparing pie (Photo Credit: Patrick Tran)

Elliot Cheung hard at work preparing pie (Photo Credit: Patrick Tran)

These pie researchers calculated the elastic modulus of each crust to further quantify flakiness. Elastic modulus of a substance is the ratio of the stress applied to the resulting strain. This ratio can be thought of as a measure of  stiffness, or in our case, flakiness, as the flakiest crust will break the most easily. 

Pie crusts that utilized both forms of beer had a higher average elastic moduli than crusts with other binding agents.

Pie crusts that utilized both forms of beer had a higher average elastic moduli than crusts with other binding agents.

Pie crusts with Perrier as a binding agent yielded the greatest average heights

Pie crusts with Perrier as a binding agent yielded the greatest average heights

They administered force to their crusts by using a pen to mimic the conditions of fork prongs stabbing a pie crust. Measured values of water balanced atop the pen acted as a weight to provide precise values of force.

Through this extensive research, P.I.E. presented data that showed that a pie crust made with Perrier sparkling water created a significantly thicker crust than one made with any of the other experimental liquids. All the other crusts surprisingly rose to very similar heights.  Since P.I.E had observed similar bubble size and bubble concentration in Perrier and beer, they expected that the regular beer crust would yield similar data to the Perrier crust. However, the significant difference between the measured values  of Perrier and beer imply a confounding factor in the experimental comparison. They speculate that Perrier’s high mineral content could alter the vaporization temperature of the liquid, and thus affect the creation of air bubbles and the dough’s infrastructure.

The dedication to detail and the scientific method paid off for these three scientists, as the panel of esteemed judges awarded them the title of “Best Scientific Pie”. As this was a scientific bake off, that is a pretty high honor to hold. Congratulations to the Pretty Intense Pie Enthusiasts, and we thank you for your deliciously scientific dessert!

Christina Cheung, Tori Schmitt, and Elliot Cheung accept their awards for Best Scientific Pie

Christina Cheung, Tori Schmitt, and Elliot Cheung accept their awards for Best Scientific Pie (Photo Credits: Patrick Tran)

Recipe
Beer Crust Apple Pie

(Makes two full pies)

For crust:

  • 5 cups flour
  • 2 TB sugar
  • 2 t salt
  • 4 sticks chilled butter
  • 1/2 to 1 cup cold beer (we used Blue Moon, but any pale ale works here)

Combine flour, sugar, and salt in a large bowl. (if making full recipe will require a very large bowl) Cut chilled butter into cubes and cut into flour mixture with a fork or pastry cutter.  The flakes can vary in texture but absolutely no butter cubes should remain intact. The mixture will resemble corse sand.  Measure out beer starting at 1/2 cup.  Pour in and incorporate into dough. If dough is still dry, incorporate more beer in until the dough is just moist enough to stick together.  Wrap dough in saran and refrigerate for at least 30 minutes, up to overnight.

For Filling and Assembly:

  • 8 large apples (we used a mixture of granny smith and pink lady)
  • 1 cup sugar
  • 6 tablespoons flour
  • salt and cinnamon to taste
  • Lemon zest (roughly 2 TB)
  • one bottle of beer or hard apple cider
  • egg white to brush the top with
  • 1/2-3/4 cup of shredded gruyere cheese

To prep the filling, core and peel all your apples and soak them in enough beer and/or hard cider to cover for 1-2 hours or until the apples are infused to taste. Pour out liquid and reserve for reduction sauce later. Be sure to remove all the liquid from the bowl and allow the apples to dry for roughly 30-45 minutes.  The apples will look significantly less “wet” after the drying period.  After the apples are dry, combine them with flour, sugar, lemon zest, cinnamon, and salt.  Depending on the sweetness of your hard cider/beer, you may need to adjust the amount of sugar used.

Assembly:

Pre-heat home oven to 500 degrees. Section pre-chilled pie dough into four equal segments and roll out two of the pie dough segments. Place these over buttered glass pie dishes and fold into place. Split filling evenly and pour into each dish. Dot top of apples if additional butter if desired (roughly 1 TB per pie).  Roll out the remaining pie crust into two top pieces.  Sprinkle each top pie with an equal amount of cheese.  Cheese amount will depend on strength and personal preference for cheese.  Flour pin well and lightly roll/ press cheese gently into the crust (dough will be very flaky).  Lay top crust evenly over pie with cheese side facing up. Crimp edges and brush with egg whites.

To bake the pie. place and oven and lower temp to 425 degrees F.  Bake at this temp for 25 minutes at which point, rotate the pie and lower temp to 375 for an additional 30-35 minutes. This will produce a pie with softer apples.   Alternatively the pie can be baked at 375 for a full hour, however the apples may remain more al dente.  (Pie was baked in the second way for competition)


Elsbeth SitesAbout the author: Elsbeth Sites is pursuing her B.S. in Biology at UCLA. Her addiction to the Food Network has developed into a love of learning about the science behind food.

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Boozy Apple Pie

On foraging for local ingredients in your college dormitory…

Our Judge’s Favorite winner of the 2013 Science of Pie event showed how beer and vodka affect pie crust color and texture. But they weren’t the only students who experimented with alcohol in their pies. Two other teams—Team Super Rum and the Beam Team—also used alcohol to create flaky, tender crusts. The Beam Team even added Kentucky bourbon whiskey (Jim Beam, of course) to their pie filling for an extra punch of flavor.

So why all the alcohol? According to the Beam Team:

“Our group was inspired by Alex Atala’s process of going out into the Amazon Forest and finding local plants to use as ingredients. As college students, we decided that our ‘native’ ingredient is alcohol since it is easily found in abundant quantities all around us, so we used our two favorite types of hard alcohol: whiskey and vodka.”

There’s another (more scientific) reason for boozing up a pie crust: alcohol creates a more tender, flaky crust than can be easily achieved with water alone. This happens because alcohol and water have very different effects on the formation of springy gluten networks in pie dough.

Gluten develops when two wheat proteins in flour, glutenin and gliadin, are mixed with water. Because parts of these proteins do not like to interact with water, the proteins begin to stick to each other much in the same way oil droplets come together when suspended in water. As a flour-water dough is mixed, the glutenin and gliadin molecules interact to form an extensive elastic network [1].

Gluten development during dough formation. Scanning electron micrographs of gluten networks during early (A), middle (B), and late (C) stages of dough mixing [2]. The development of these gluten networks requires water.

While gluten networks are great for chewy bread dough, they are less than ideal for flaky, tender pie crust. An ideal pie dough has as just enough gluten to hold everything in the dough together. And while gluten development can be minimized by adding only scant amounts of water and handling the dough as little as possible, this is easier said than done.

A more practical solution is to replace some of the water with a liquid that does not promote gluten formation. Unlike water, alcohol inhibits gluten formation. By interacting with the gluten proteins, alcohol molecules limit their ability to stick to each other and form springy networks [1]. Using alcohol in the place of water allows more liquid to be added to the dough while still restricting gluten formation. This results in a softer, more pliable dough that becomes tender and flaky when baked.

TeamSuperRum

Team Super Rum serves their pie and presents their work at the Science of Pie even (left). Test pies made with rum pie crust (top right) or bourbon apple filling (bottom right).

Like the recipe below, the Beam Team paired a vodka pie crust with a decadent bourbon and apple filling. Although vodka is typically used for its subtle flavor, any type of alcohol will prevent gluten formation. As their name suggests, Team Super Rum used rum instead of vodka to create a flaky and uniquely flavored crust. And we bet there are many more delicious possibilities in the realm of alcohol-based pie crusts. If you try this recipe with something other than vodka, share your new pie crust concoction with us in the comments below!


Foolproof Vodka Pie Crust

Cook’s Illustrated, November 2007

2 1/2 cups (12 1/2 ounces) unbleached all-purpose flour
1 tsp table salt
2 tbsp sugar
12 tbsp (1 1/2 sticks) cold unsalted butter, cut into 1/4-inch slices
1/2 cup cold vegetable shortening, cut into 4 pieces
1/4 cup cold vodka
1/4 cup cold water

Process 1 1/2 cups flour, salt, and sugar in a food processor until combined, about 2 one-second pulses. Add butter and shortening and process until homogeneous dough just starts to collect in uneven clumps, about 15 seconds (dough will resemble cottage cheese curds and there should be no uncoated flour). Scrape bowl with rubber spatula and redistribute dough evenly around processor blade. Add remaining cup flour and pulse until mixture is evenly distributed around bowl and mass of dough has been broken up, 4 to 6 quick pulses. Empty mixture into medium bowl.

Sprinkle vodka and water over mixture. With rubber spatula, use folding motion to mix, pressing down on dough until dough is slightly tacky and sticks together. Divide dough into two even balls and flatten each into 4-inch disk. Wrap each in plastic wrap and refrigerate at least 45 minutes or up to 2 days.


Bourbon Apple Pie Filling

2 tbsp all-purpose flour
6 or 7 apples, mix of tart and sweet
1/3 cup sugar
1/2 tsp cinnamon
1/2 tsp nutmeg
1/4 tsp salt
1/2 cup bourbon whiskey
2 tbsp lemon juice
2 tbsp butter cut into small pieces

Preheat oven to 425. Place bottom crust in pie plate.

Peel, core, and halve the apples. Cut into 1/4-inch thick slices, about 7 or 8 cups.

In a 4 quart saucepan, whisk together sugar, flour, cinnamon, nutmeg, and salt. Whisk in bourbon whiskey and lemon juice until evenly blended. Cook over medium heat, whisking frequently until the mixture boils and thickens slightly. Add apples and stir until evenly coated. Continue cooking, stirring continuously, for 3 minutes. Set aside to cool, stirring once or twice for 20 minutes.

Pour apple mixture into the pie shell, mounding apples slightly in the center. Dot with butter and add the top crust. Cut several steam vents into top crust.

Bake 25 minutes at 425. Reduce temperature to 350 and bake 45 minutes longer or until crust is brown and juices are bubbling.

Serve warm or chilled with whipped cream or ice cream.


Online Resources

  1. Pie crust recipe from Cook’s Illustrated via Serious Eats
  2. Bourbon apple pie filling recipe adapted from Group Recipes


References Cited

  1. Technology of breadmaking (2007). 2nd ed. New York: Springer. 397 p.
  2. Amend T (1995) The mechanism of dough forming: Efforts in the field of molecular structure. Getreide Mehl Brot 49: 359–362.

Liz Roth-JohnsonAbout the author: Liz Roth-Johnson is a Ph.D. candidate in Molecular Biology at UCLA. If she’s not in the lab, you can usually find her experimenting in the kitchen.

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