Saturday, February 26, 2011

Coffee Liqueur .

Coffee Liqueur
Andre Willers
25 Feb 2011

Synopsis :
How to make sugar-free Coffee Liqueur with carb-count = 0 and alcohol volume of 25% .

Discussion :

General method :
For one standard 750 ml bottle of Coffee Liqueur :

Method :
1.Make about 300 ml of coffee syrup using the cold brew method .
See previous posts or Google it .
Briefly , 3 –4 tablespoons of coarsely ground coffee beans of decent quality (I like Columbian) in a plunger with about 350 ml water (cup and a half) .
Put in fridge for about 12 hours . Push plunger home and decant clear coffee syrup .

2. Add sweetener . The coffee syrup is more bitter than ordinary coffee .
Add enough for about 4 cups of coffee . To taste .
Those fortunate ones that do not have to worry about sugar or carbs can use sugar .

3. Pour about 280 ml of the syrup into your 750 ml bottle . Top up with your alcohol of choice . Whisky , cane ,vodka etc .These are usually about 40% alcohol by volume. This is stated on the bottle .

4. Pour into a liqueur glass and enjoy !

Caffeine concentration :
See Appendix A below .

Cold brewing gives a slightly higher caffeine concentration than hot brewing .
The three tablespoons of ground coffee used above would be the rough caffeine equivalent of two cups of hot brewed coffee in the syrup .
A bottle would then contain after dilution 281/468 *2 = 1.2 cups of hot brewed coffee caffeine .
A liqueur glass is 25 ml . This then has the equivalent caffeine of 1.2*25/750 = 0.04 of a cup of hot brewed coffee (4 %) . This will not exactly keep you awake .

The really interesting thing here is whether this ratio of caffeine to alcohol balances the depressant effects of alcohol and the stimulant effect of caffeine at a stable level . Cf Irish Coffees .

Note the popularity of caffeine boosted mixers like Coke or Red Bull .

As an exercise , the Dear Reader can calculate the exact peak point of the interaction .
A lot of experimental evidence will be required .
Hint : Try shooters of coffee and tequila in varying ratio's .

Who says science is not fun ?



Appendix A
Some calculations :
The general relationship is
{ V(1)*A(1) + V(2)*A(2) } / {V(1)+V(2) } = A(3) …(Eq1)
where V denotes Volume and A denotes Alcohol concentration per volume .

The Right-Hand of the equation A(3) means the alcohol concentration of your liqueur. This is usually about 25% . Drinkable in small sips . Hence the liqueur glass .
V(1) and A(1) means the Volume and Alcohol concentration of your booze .
A(1) is typically 40% per volume . Cane , whisky , vodka , etc . See the bottle .

V(2) and A(2) means the Volume and Alcohol concentration of your Coffee Syrup .
There is no alcohol , so A(2) =0 .

The left-hand of the equation is the weighted average of the two concentrations , weighted by volumes .

We merely plug in the values into (Eq1)
A(3) = 0.25
V(1)+V(2) = 750 ml (our bottle)
A(2) = 0 The Coffee Syrup has no alcohol .

This gives booze volume
V(1)* 0.4 = 750 * 0.25
V(1) = 750 * 0.25 / 0.4
V(1) = 468.75 ml
Hence coffee syrup volume
V(2) = 750-V(1)
V(2) = 281.25

Round as you please
281/750 = 0.37 . Filling the bottle about a third with Coffee syrup and topping up with booze should be ok .

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