I am interested in the caffeine content in various coffees.
Will day-old coffee have much less caffeine? I am refering to espresso drinks such as the Starbucks Americano or the drip coffees also available there. Does refrigeration make much difference to the half-life? What about re-heating?
How about instant? I have seen charts comparing caffeine content in various fresh coffees but not instant. What is the typical caffeine content of instant coffee? What is the half-life of caffeine in instant coffee on the shelf as a room temperature solid?
According to Sigma-Aldrich, pure caffeine has a shelf-life of four years at room temperature, or many years at 2-8°C.
A caffeine solution can be stable for months even at moderately high temperatures.
So, essentially, your day old coffee has still all its caffeine in it, although probably it does not taste that well, but that's caffeine unrelated.
As a side note, after drinking coffee/tea/Coke/etc. it will take ~1-2 hours for blood caffeine levels to peak. Caffeine half-life in the body is ~3-6 hours.
Over the last few years I had come to believe that the roasting process for bold coffees removed caffeine from the beans resulting in a lower caffeine content than compared to a light roasted coffee... the opposite claim. Also, comments the page have pointed to sources describing the inconsistency of caffeine levels: Caffeine content by roast level and Does dark roast coffee have less caffeine than light roast? Searching around on .edu sites I find charts that seem to support the idea that bolder coffees contain more caffeine. The charts show smaller amounts of bold coffee (2-4oz) contain the same amount
I had gone completely cold-turkey on caffeine for a while due to anxiety issues, and I'm slowly reintroducing caffeine to my diet. I have read in many places that freeze-dried instant coffee has less caffeine than the equivalent amount of fresh-brewed, but I haven't seen any explanations as to why. Is it something inherent to the freeze-drying process which causes this change? And, of course, how much lower is the caffeine content in general?
I've recently gotten a Cafe Press for making my coffee, and I'm pretty bad with proportions. If I make too much and leave it sitting in the press with the grounds pressed to the bottom, does the coffee on top keep 'brewing'? Does it otherwise adversely affect the flavour? Does it affect the caffeine content?
Many recipes for chocolate baked goods call for instant espresso powder. I rarely bake, but I always have coffee in the house. What might I use as a rule of thumb for substituting for instant espresso powder? I know I could substitute regular coffee for any liquids, but that could add too much liquid to some recipes. Would double or triple strength brewed (or French Press) coffee work? Is the flavor significantly different in the instant powder than in brewed coffee? Or is it simply the quick dissolve and the lack of liquid that makes the powder appealing in baking?
Came in to work this morning and made a round of coffees, the same as yesterday. To freshly washed and fully rinsed mugs, I added instant coffee, and the milk then filled with boiling water... bought fresh milk and repeated. The same thing happened. We are using the same kettle as yesterday, the same mugs, the same instant coffee. To be sure it was the milk, I made a coffee with just coffee... milk jugs. Please help, I had a few beers last night and need my coffee!
I have a recipe for a chocolate buttermilk cake. It's not constructed like most cakes, but it's always turned out OK. I've always wondered what does the coffee in the recipe do? Is the coffee just there as an additional flavor? (The cake never tastes strongly of coffee.) Can I use a cheap instant coffee, or will a higher quality coffee make a difference? Does the acid in the coffee do something? Does the temperature of the coffee really matter? Here's the recipe: 3 cups flour, 2 1/2 cups sugar, 1 1/2 tablespoons baking soda, 1/2 tsp salt, 1 cup unsweetened cocoa powder, 1 1/3
tastes burnt. So burnt that I've had to throw it away. This isn't specific to one particular brand of instant coffee, I have tried 3 brands. I've noticed that it seems less burnt if I put it in the microwave for lesser time, but I like my coffee piping hot in the morning and it doesn't turn out well. So what is it about microwaving instant coffee that makes it taste so revoltingly burnt and what...First off, I did see this question about reheating the coffee in a microwave oven, but the answer merely suggested that stale coffee tastes bad irrespective of the microwave. I make instant coffee
Okay so I have a french press, and I have been trying to figure out how much coffee I need. Here is the scenario: It is a 15 oz press, I been reading that the general rule of thumb is 2 tbs of coffee per 6 oz of water, so if my math is correct that would me 5 tbs of coffee. or roughly 25 grams... This seems like a lot of coffee for that amount of water? Secondly, do I measure the scoops prior to grinding or after grinding? I know there isn't an exact answer and there are other variables to consider, but I was wondering if there are any general guide lines I should be following
Possible Duplicate: What is the difference between various types of flour? I am baking a Yule Log (Buche de Noel) for solstice and the recipe I generally use calls for a lot of coconut and pecans and I have people who don't like those things coming to dinner, so I am looking for another recipe. The recipes I am finding though all call for cake flour and I don't bake a lot of cakes so I didn't want to buy it just for this recipe, can I turn AP flour into cake flour or what is the difference between the two? I have bread flour and AP flour in the pantry.