Excellent idea. Makes sense, since the acidity and character begins to go away as coffee continues to stale.
------------------------------------------ ----------------------------------------- Le café doit être noir comme le diable, chaud comme l'enfer, pur comme un ange, et doux comme l'amour.
"There is no right answer with coffee. There is only the elixir in your cup at the moment you partake."
"...I often say that when you can measure what you are speaking about, and express it in numbers, you know something about it; but when you cannot measure it, when you cannot express it in numbers, your knowledge is of a meagre and unsatisfactory kind;..." - Lord Kelvin RECIPES thread => http://www.coffeegeek.com/forums/coffee/machines/585708
Using water from distilled to 16(approx) grains hardness, the effect on resulting cold brewed coffee at 15% brew ratio 24 hour contact time is...
...nothing.
Personally, I am unable to distinguish same strength coffee made cold brewing with distilled or hard water, except a bit more scum on top of a "reconstituted" batch brewed with very hard water. This is a byproduct discovery on my latest batch of coffee brewing investigations. This last bunch was done with using varying harness for both the brewing and the reconstitution stage. (i.e. brewed with distilled, reconstituted with distilled, brewed with distilled, reconstituted with hard water, and the reverse of each).
Extraction with either water was identical within measurement error - just about 17+% extraction (technically underextracted).
So, if you're cold brewing, so long as your water doesn't have off flavors (iron or sulphur) don't worry about hardness. I think I'm understanding why, and it's related to the muted brightness and acidity of cold brewed or underextracted coffee (what people normally call "smooth").
I guess I wasn't completely done with cold brewing, but now I am... for now, I guess.
------------------------------------------ ----------------------------------------- Le café doit être noir comme le diable, chaud comme l'enfer, pur comme un ange, et doux comme l'amour.
"There is no right answer with coffee. There is only the elixir in your cup at the moment you partake."
"...I often say that when you can measure what you are speaking about, and express it in numbers, you know something about it; but when you cannot measure it, when you cannot express it in numbers, your knowledge is of a meagre and unsatisfactory kind;..." - Lord Kelvin RECIPES thread => http://www.coffeegeek.com/forums/coffee/machines/585708
hey! i love your experiment here but quite honestly i'm a little lost...any chance you might be able to break it down for me? would love to know what you recommend... how many ounces of coffee with how much water and how long you suggest i let it soak for? you'd be doing me a huge favor :) thanks ~ella
hey! i love your experiment here but quite honestly i'm a little lost...any chance you might be able to break it down for me? would love to know what you recommend... how many ounces of coffee with how much water and how long you suggest i let it soak for? you'd be doing me a huge favor :) thanks ~ella
I use an Aeropress to separate the grounds. I bet you could use any variety of several types of filtering system.
The only reliable way to do amount of coffee is by mass: 15% "brew ratio" is what I would recommend.
Using 50 fluid oz (6 1/4 cups) of brew water, you need 222 grams of coffee (7.8 oz by weight, or about half of a 1/2 lb package). [math behind it is 50 fluid oz of water = 1478g of water, multiplied by 15% is 222g of coffee, or approximately half a lb]
You can scale up or down from there, keeping the same ratio:
For every cup of brew water, use about 8.3 oz of ground coffee.
Steep for between 12 and 24 hours, and filter. Get a bit more flavor by using hot tap water, before you put the grounds in the fridge.
Remember you will have to dilute the result to taste, it will be coffee concentrate. If you follow this ratio, I would start with diluting it 2 parts water to 1 part concentrate, unless you're making iced coffee.
Hope that helps.
------------------------------------------ ----------------------------------------- Le café doit être noir comme le diable, chaud comme l'enfer, pur comme un ange, et doux comme l'amour.
"There is no right answer with coffee. There is only the elixir in your cup at the moment you partake."
"...I often say that when you can measure what you are speaking about, and express it in numbers, you know something about it; but when you cannot measure it, when you cannot express it in numbers, your knowledge is of a meagre and unsatisfactory kind;..." - Lord Kelvin RECIPES thread => http://www.coffeegeek.com/forums/coffee/machines/585708
Do you know if it is feasible to concentrate it further? I don't mean by starting with a higher brew ratio (which you found to be a bad idea), but through freeze concentration?
Do you know if it is feasible to concentrate it further? I don't mean by starting with a higher brew ratio (which you found to be a bad idea), but through freeze concentration?
Seriously, I doubt it, not with purely cold brewing. You're looking for high concentration with partial extraction, where extraction and the brew ratio are inversely related, and it's just not possible.
Here's why:
if you have 100g of coffee, and you extract 17% of it, you have 17g of coffee solids.
if you use a 15% brew ratio, you extracted it with about 667g of water, and yielded around 480g of coffee. 17g / 480g is about 3.5% strength or about triple normal strength.
We already know we can get the strength up by reducing the brew water, but we get less extraction like you said and like my experiment. Going the other way (more water or decreasing the brew ratio) might increase extraction, but the end will have more water and end up less strong.
Freezing coffee has never turned out to be anything more than a curiosity for me. Frozen and reconstituted coffee tastes really flat to me, so I expect that if you take cold brewed coffee concentrate, freeze it and try to dry-freeze it, then thaw it into essentially a beverage with all the solids but less water... I imagine this will prolly taste not so good.
Freeze drying takes a long time, too.
I'll noodle on it, but right now I can't think of a way to do that using strictly cold brew coffee.
Now, you COULD hot charge and cool the brew overnight. I have not tried this FULLY, but I essentially do this most nights for quick coffee in the morning (brew 4%-5% strength coffee concentrate with an Aeropress, cover and refrigerate overnight, reconstitute in the morning with piping hot water) except I don't leave the brew in contact overnight. This gives me top-notch coffee in the morning with the speed of a single-cup brewer.
An example of this potential technique (hot charge cooled steep brewing): 100g coffee, use 667g of JUST OFF BOIL water. Mix and cover in a french press, put in the fridge.
12 hours later, separate the grounds and you'll probably have a concoction of 22% extracted coffee, but cold. Filter it out and you'll have ~480g of coffee but you have 22g of dissolved solids - or about 4.5% strength instead of 3.5% strength.
Furthermore, you could easily push the brew ratio higher but since you're stating the steeping with hot water, you'll probably get full (or maybe even over) extraction. Goofing around with brew ratios and aeropress brewing, I've gotten strengths up to as high as 10% with full extraction.
In the above example, 100g coffee, but 31% brew ratio (320 g water - JUST OFF BOIL). If this achieves 22% extraction, you end up with ~220g of coffee concentrate with 22g dissolved solids or a 10% strength concentrate.
One must question whether you actually get much more extraction after the initial hot charge and subsequent cooling, though. Lot of trouble just to get a concentrated coffee.
------------------------------------------ ----------------------------------------- Le café doit être noir comme le diable, chaud comme l'enfer, pur comme un ange, et doux comme l'amour.
"There is no right answer with coffee. There is only the elixir in your cup at the moment you partake."
"...I often say that when you can measure what you are speaking about, and express it in numbers, you know something about it; but when you cannot measure it, when you cannot express it in numbers, your knowledge is of a meagre and unsatisfactory kind;..." - Lord Kelvin RECIPES thread => http://www.coffeegeek.com/forums/coffee/machines/585708
Now, you COULD hot charge and cool the brew overnight. I have not tried this FULLY, but I essentially do this most nights for quick coffee in the morning (brew 4%-5% strength coffee concentrate with an Aeropress, cover and refrigerate overnight, reconstitute in the morning with piping hot water) except I don't leave the brew in contact overnight. This gives me top-notch coffee in the morning with the speed of a single-cup brewer.
So you sometimes hot brew the night before? I would have thought that you'd lose aromatics that way, unless you could cool the coffee very quickly. This is the reason I was interested in cold brewing in order to make a concentrate. But if there is no appreciable loss in flavor then cold brewing provides no advantage for what I am interested in (and this is the wrong thread).
I have never tried repeatedly freezing coffee in order to concentrate it so I don't have a feel for how far this could be pushed. Is a 50% concentrate achievable?
So you sometimes hot brew the night before? I would have thought that you'd lose aromatics that way, unless you could cool the coffee very quickly. This is the reason I was interested in cold brewing in order to make a concentrate. But if there is no appreciable loss in flavor then cold brewing provides no advantage for what I am interested in (and this is the wrong thread)....
Yes, I do. There is a bit of loss of aromatics, but it is minimal - the amount that I brew (yields about 100g) cools within about 15 minutes, and it's sealed right after pressing. The result when reconstituted is FAR superior (freshly roasted, freshly ground just before brewing, properly extracted) to anything that a single cup brewer can make.
jpender Said:
... I have never tried repeatedly freezing coffee in order to concentrate it so I don't have a feel for how far this could be pushed. Is a 50% concentrate achievable?
Me neither, but I think it is probably not worth even trying. Cold brewed coffee concentrate, IMHO, already lacks some of the coffee's flavor profile. Further concentrating it by freeze drying seemed not worth the effort of investigating.
HOWEVER, if you try it, please post the results.
(I'm basing this on past evaporation checks that I do to check extraction and total dissolved solids. If I reconstitute evaporated solids, I get something coffee-like but very weird and flat flavor profile. It almost tastes like... well if you had it you wouldn't call it coffee right off. Tastes boiled? Like half of the flavor profile is missing? Off? Not exactly spoiled... you'll have to try it yourself. Just take a cup of coffee, and put it in the oven at 215°F until all of the water evaporates. Then, put the amount of water that evaporated back in and stir to re-dissolve the solids, and taste it. :D You prolly won't thank me that you did... ;-) )
Also, I've had good luck with stepped brewing or staged brewing.
Basically, you re-brew cold brewed coffee using the same grounds, in steps of steep time.
------------------------------------------ ----------------------------------------- Le café doit être noir comme le diable, chaud comme l'enfer, pur comme un ange, et doux comme l'amour.
"There is no right answer with coffee. There is only the elixir in your cup at the moment you partake."
"...I often say that when you can measure what you are speaking about, and express it in numbers, you know something about it; but when you cannot measure it, when you cannot express it in numbers, your knowledge is of a meagre and unsatisfactory kind;..." - Lord Kelvin RECIPES thread => http://www.coffeegeek.com/forums/coffee/machines/585708
(I'm basing this on past evaporation checks that I do to check extraction and total dissolved solids. If I reconstitute evaporated solids, I get something coffee-like but very weird and flat flavor profile. It almost tastes like... well if you had it you wouldn't call it coffee right off. Tastes boiled? Like half of the flavor profile is missing? Off? Not exactly spoiled... you'll have to try it yourself. Just take a cup of coffee, and put it in the oven at 215°F until all of the water evaporates. Then, put the amount of water that evaporated back in and stir to re-dissolve the solids, and taste it. :D You prolly won't thank me that you did... ;-) )
I can believe that. But hot evaporation of a liquid composed of many different volatiles isn't going to produce the same end product as freeze concentration will.
I guess I'll brew up a sample (hot) and then freeze it just to see what it looks like. I'm not sure I've ever seen frozen coffee before.
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