August 2011: Cold Brew Experimentation

Apparently, it feels like summertime in all corners of the United States that aren’t West Oakland and, although nothing replaces a hot cup of coffee, we understand that many of our customers are looking for a refreshing iced beverage to help ease those hot August days. With this in mind, we tested brewing methods for iced coffee and want to share the results.

Our experiment was based on three commonly-used methods: brewing a regular pot of hot coffee and sticking it in the fridge; cold-brewing a coffee concentrate to later be diluted over ice; and brewing hot concentrated coffee directly over ice. Since we were seeking a sweet, clean cup with a unique flavor profile, we selected a washed Ethiopian coffee, Guji Suke Quto, for the test. Each cup tasted surprisingly unique and besides an all-around consensus against the chilled pot of hot-brewed coffee, each method had its benefits.

We began the experiment a day before our anticipated tasting and started off with a relatively straight-forward method, refrigerating a carafe of filtered coffee made with a Technivorm.  As previously mentioned, nobody at Sweet Maria’s would endorse this practice based on the results.  Flavor descriptors included dirty, stale, coffee-breath and “blech,” and Tom actually checked the coffee for sediment due to its perceived grittiness.

The cold brew took a bit more preparation and some ingenuity in the kitchenette. We started with a recipe from a New York Times article that recommended steeping one half-pound of coffee in five cups of cold water overnight. We ground the beans at a coarse setting and set up two samples in beakers to be refrigerated for 24 hours.

The following afternoon, we poured one sample through a mesh kitchen strainer to eliminate the grounds before passing it through a paper filter. The other sample was pressed right in the beaker and strained through the french press filterscreen. The resulting coffee concentrates measured 2½ cups each, which we then diluted with equal parts water.

Although the taste test was blind, the differences between the cold brews and the Technivorm were tremendous. Cold brewing resulted in sweet, flavorful cups with a mellow acidity. The floral and citrus notes were obviously apparent, but so were the lower, sweeter tones. Between the two cold brews, most preferred the filtered cup. As you would imagine, the french pressed cold brew had a heavier body than its filtered counterpart, but lacked flavor clarity.

Immediately after our initial test, we decided to brew one last sample via a technique that several of our customers recommended. We prepared a Clever Coffee Dripper with twice our usual dose of ground coffee, poured in 350mL of water and released it over 350g of ice after four minutes of steeping. We found this method to yield an instantly refreshing, light-bodied brew quite different from the cold brew methods. It emphasized the bright floral and fruited aspects of the coffee and, although it lacked the low notes present in the cold brew, it was COLD.

After a repeat test between the filtered cold brew and the hot concentrated Clever-brewed coffee, the majority of us still prefer cold-brewed iced coffee. It seems to result in a fuller-bodied beverage that emphasizes sweetness while retaining the unique origin characteristics. That being said, if you’re looking for quick iced coffee with an easy clean-up, a stiff Clever on the rocks may be the way to go.

Some Cold Coffee Notes:
Iced coffee is commonly referred to as “toddy” after a company who popularized cold concentrates with a system that essentially replicates our cold brewing experiment. Brewing over ice is known as the Japanese iced coffee method and can be employed using any pourover brewer: Hario, Chemex, etc. To make a single cup, replace half of the amount of water with an equal volume of ice.

Experiment Details/Results:  Coffee used was Ethiopia Guji Suke Quto roasted in a Behmor to Full City

Method 1

Technivorm brewed hot and refrigerated 24 hours

5 scoops coffee; 8 cups water; Grind for drip.

Notes: ranked least favorite by all. dirty; gritty; stale-tasting; coffee breath

Method 2

Cold Brew – Steeped 24 hours in refrigerator and filtered with paper

½ lb. coffee; 5 cups water; Grind coarse for press pot

Coffee concentrate mixed 1:1 with water

Notes: pleasant; highly fruited; mellow acidity; best flavor clarity

Method 3

Cold Brew – Steeped 24 hours in refrigerator and first stained through mesh and then

One batch strained through French Press

One batch strained using a Paper Filter (*this method was preferred)

½ lb. coffee; 5 cups water; Grind coarse for press pot

Coffee concentrate mixed 1:1 with water

Notes: heaviest body; preferred by some; less flavor clarity than filtered alternative

Method 4

Concentrated Clever brewed over ice

44 grams coffee; 350 ml water; Grind for drip.

Steep 5 min Brewed over 350g ice

Notes: Better than chilling hot coffee, Tom prefers this method feeling it is more refreshing but still prefer flavors in cold brew.

Some Cold Brew Coffee Recommendations:
Guatemala Finca Candelaria:  Classic Guatemala coffee in terms of brightness and roast development. A great “daily drinker” coffee.

 Sumatra Dry-Hulled Aceh Bukit: A cleaner cup profile than typical Sumatra coffees, brighter relative to other Indonesia coffees, but still very Sumatra-like in character. Similar to our wet-process Sulawesi coffee.

 El Salvador Santa Ana Naranjo:  While the coffee is brighter and livelier as a City roast, Full City has a deep sweetness and balance.

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