Scientific Ice Brew Coffee Brewer Kit

Transcription

1 Scientific Ice Brew Coffee Brewer Kit Apparatus Guide

2 The Science Behind the Cold-Brewed Cup: Dating back to the 1600s in Japan, cold-brew coffee is a brewing technique that has been known for centuries. Cold-brew is sometimes known as Kyoto coffee or Dutch coffee, as it was supposedly introduced to Japan by Dutch traders from Indonesia. The slow-drip process creates a concentrated elixir of coffee by extending the extraction process over a period of hours instead of minutes. The traditional process of brewing coffee with high temperatures changes the coffee at the molecular level in addition to the extracting the coffee. The interaction of heat with the ground coffee can modify the oils found in the coffee and introduce undesirable flavors when extracted. The cold-brew process bypasses the molecular changes by extracting the coffee solubles at single digit degree Celsius temperatures. This results in a smoother, less acidic, cup of coffee. Solubility: The ability of substances to dissolve in a solvent is called solubility. In the case of brewing coffee, the solvent is water, and the resultant coffee is a solution. In general, substances are more soluble at high temperatures (think of sugar dissolving more quickly in hot coffee than cold). Some of the elements in the ground coffee beans are much more resistant to extraction at low temperatures. Extracting over a period of hours instead of minutes ensures much of the desired solubles will extract. Acidity: The elements that contribute to the taste of acidity or sourness in a cup of hot brewed coffee are muted in the cold brewing process. The resulting cup will have a much mellower palate, even when brewing with traditionally highly acidic beans. Concentration: By design, the initial coffee/water ratio for the cold brew technique produces a more concentrated strength coffee. The resulting brew can have up to twice the strength of hot brewed coffee in terms of strength of flavor and viscosity. Volatility: Volatility is the ability of substances to vaporize, and become airborne. Hot liquids will be much more volatile than cool liquids, and that is why hot coffee is much more aromatic. Unfortunately that means that flavor is leaking away from your cup of hot coffee. By cold brewing, much of that flavor does not have the chance to escape through the air and is instead retained inside the brew.

3 Oxidation: The reaction of substances with the oxygen in air is generally an undesirable thing when it comes to taste. Oxidized coffee oils cause a bad taste to develop in the brewed coffee. Oxidation happens much more quickly at high temperatures, so cold brewing decreases the rate of oxidation, keeping the bad flavors out of the coffee for a longer amount of time. Shelf-life: Due to the factors listed above, cold brewed coffee will have a longer shelf life than hot brewed coffee. Cold brewed coffee will resist developing bad flavors and the taste will remain stable for 24 hours or more when refrigerated. Kit Contents: 12 Heavy Duty Base 40 Stainless Steel Rod 1000 ml Borosilicate Separating Funnel Pear Shaped 20 cm Porcelain Buchner Funnel 2 Heavy Duty Orthogonal Bossheads 2 Cork Lined Flask Clamps cm Ring Clamps with Bosshead 600 ml Borosilicate Beaker 500 ml Borosilicate Beaker Mug Polypropylene Stopper

4 Set-up: Stopper Heavy Duty Bosshead Cork Lined Flask Clamp 1000 ml Borosilicate Separating Funnel Pear Shaped 7.5cm Ring Clamp with Bosshead 40 Stainless Steel Rod 20 cm Porcelain Buchner Funnel 7.5cm Ring Clamp with Bosshead Heavy Duty Bosshead Cork Lined Flask Clamp 600 ml Beaker 500 ml Beaker Mug 12 Heavy Duty Base

5 Set-Up Instructions: 1. Screw the 40 Stainless Steel Rod into the hole on the long side of the Heavy Duty Base. Be sure to screw in as tightly as possible. 2. Attach one green Heavy Duty Bosshead onto the Stainless Steel Rod. Tighten using the thumbscrew. This bosshead should be about 7 inches above the base. 3. Attach one of the 7.5 cm Ring Clamps with Bosshead so the ring is 3.5 inches above the Heavy Duty Bosshead. Tighten with thumbscrew. 4. Insert one of the Cork Lined Flask Clamps into the Heavy Duty Bosshead. Situate so the head of the clamp is centered below the ring clamp. Tighten with thumbscrew. 5. Attach the second 7.5 cm Ring Clamp about 12 inches above the lower ring clamp. 6. Attach the second green Heavy Duty Bosshead on the rod about 6 inches above the second ring clamp. 7. Insert the second Cork Lined Flask Clamp into the Heavy Duty Bosshead. Situate so the head of the clamp is about centered above the ring clamp. thumbscrew. Tighten with 8. Open the lower Cork Lined Flask Clamp using the thumbscrew. Place the 20 cm Porcelain Buchner Funnel into the lower Ring Clamp. It may be necessary to adjust the height of the Flask Clamp, try to situate so the bottom of the funnel should reach just below the Flask Clamp. Tighten the Cork Lined Flask Clamp on the funnel. See above Figure. 9. Open the upper Cork Lined Flask Clamp using the thumbscrew. Place the 1000 ml Pear Shaped Separating Funnel into the upper Ring Clamp. Again, it may be necessary to adjust the height of the Flask Clamp, situate so the Flask Clamp is even with the neck of the funnel. Tighten Cork Lined Flask Clamp on the funnel. Do not overtighten. See above Figure. 10. Place 600 ml Beaker on the base below the Buchner Funnel. Brewing Instructions: Adding Filter Situate a large basket style coffee filter in the bottom of the Buchner funnel. Certain types of filters can be flattened into a disc, such as filters for commercial brewers are large enough to cover the entirety of the bottom of the Buchner funnel. Adding Coffee We recommend a 12 grams of ground coffee / 120ml brewed coffee ratio, so to brew a full beaker with the brewer about 60g is used to brew roughly 600ml total volume. Grind recommendation is a coarse drip grind. Spread evenly over the filter in the Buchner funnel.

6 Adding a Second Filter Flatten a second paper filter. Place on top of the coffee grinds. This step is extremely important as without the secondary filter the dripping water can bore a hole through the grinds. The top filter prevents this, and also evenly distributes the water over the ground coffee. Adding Ice Close the stopcock at the bottom of the Separating Funnel (upper chamber) by turning the knob so it is in a horizontal position. Fill the upper chamber to approximately 2/3 of the volume with ice. The size of the Separating Funnel necessitates the use of slivered ice, not ice cubes. Adding Water Add water to begin the process of brewing (this bypasses the time it would take for the ice to begin to melt). It doesn t take much water to start, 120 ml (4 oz.) is sufficient. Place the stopper in the top of the Separating Funnel. Adjusting the Dripper Adjust the stopcock so the dripping mechanism drips about one drip every one and a half seconds. Time the drips to ensure that 10 drips of water drop over a period of 15 seconds. A 600 ml brew in this device can take upwards of 5 hours. The Brewing Process It can take upwards of half an hour for the coffee grinds to completely saturate and for coffee to start to drip out of the lower filter. After several hours the ice should melt: more ice can be added to keep the temperature of the water in the upper chamber close to freezing. When the coffee in the lower vessel reaches the intended level (120 ml for every 12 g of ground coffee) stop the water dripping from upper chamber. The drops coming out of the Buchner funnel at this point should be very diluted, signifying the coffee solubles have been nearly fully extracted from the ground coffee. Enjoy a cup! The concentration of the ice-drip brewed coffee is nearly twice the strength of normal hot brewed coffee. Thus the coffee elixir should be diluted with an equal amount of cold water, and can be additionally cooled with ice. See tips below for suggestions. Storage The concentrated coffee can be stored in a refrigerator safely for 24 hour period without developing the off flavors that are usually found in a hot brewed coffee. It is recommended to store in a non-reactive container with a lid.

7 Tips: Here are some suggestions regarding drinkability for the cold-brew technique. Taste is of course subjective; you ll get the most out of your brewer by experimentation. This is a scientific brewing machine, so use the scientific process to experiment! What kind of coffee? You should use a very good quality roasted coffee for this brewing method. Generic whole beans or pre-ground commodity coffee should be avoided. Best results will be achieved with beans that have been freshly roasted within 10 days or less. How much coffee? Individual taste may vary, as well as the strength of flavor of different origin beans, but a good starting point is 12 grams of ground coffee for every 120 ml (4 oz) of brewed coffee. To fill the 600 ml beaker with brewed coffee, around 60 grams of ground coffee should then be used. What grind? This can be adjusted depending on the type of bean being used and the desired strength of the resulting brew, but it is recommended to start with a course drip grind for the first batch and grind it finer if you find the strength lacking. What type of ice and water? The equipment is designed to only hold slivered ice, not large cubes. Starting with freshly made ice, as ice that has sat long in the freezer can pick up unwanted flavors and odors. Best results can be seen with ice made from filtered water, and filtered water to prime the brewing process. What drip rate to use? The drip rate can be adjusted from a drip every several seconds all the way to a continuous flow. The goal is to keep the coffee grinds continuously saturated, not to over-submerge, so a good starting point should be about one drop of water from the upper container every one and a half seconds (40 drops per minute). It may be necessary to adjust the drip rate during the brewing process if the rate slows as the upper vessel empties. How to dilute? The coffee resulting from the cold-brewing process can be upwards of twice as concentrated as the coffee one is normally accustomed to drinking. At the completion of the brewing process, the coffee will be around room temperature, so it is recommended to add equal part ice and dilute with water to taste. If the cold brew has been stored in a refrigerator, dilute first with a near equivalent amount of water, then add ice. Use of sweetener. The colder foods or liquids are, the harder it is for many palates to taste sweetness, so sugar can be added if desired. Using an easily solvable sugar is necessary as the sugar will not dissolve as readily as it does in hot coffee. Start by adding a small amount of sugar (half a teaspoon) and adjusting to end with a balanced, not overpoweringly sweet beverage.