Why does instant coffee dissolve but regular ground coffee does not?
In: Chemistry
Regular coffee is made from beans that are ground and then when you add water, the water draws out the “coffee stuff”, the flavor and color and caffeine, etc. The stuff that doesn’t dissolve into the water stays in the bean chunks and we filter them out and throw them away.
Now take your cup of coffee and evaporate out all the water. The “coffee stuff” doesn’t evaporate and gets left behind like a dust. Instant coffee is the “coffee stuff” which has been collected and sold to you. The bean chunks have already been removed.
Instant coffee is coffee that has already been brewed and then the water removed, usually by freeze drying. Fresh coffee grounds contain plant matter that does not dissolve in water.
Making regular coffee involves passing hot water through coffee grounds to extract their contents into a liquid. The grounds themselves do not dissolve.
Instant coffee takes this a step further and dehydrates the resulting liquid to form dried coffee crystals. When you add them to water they dissolve.
Instant coffee is like dried out “just add water” coffee drink… Without actual coffee beans…
This is why regular presso is superior, but instant coffee way easier to prepare
Regular coffee: chunks of ground-up beans. They don’t dissolve because…I mean…because beans don’t dissolve. Instead, water passes through them, extracts a bunch of molecules, then comes out as coffee.
Instant coffee: take already-made coffee, and magically evaporate all the water out of it. A bunch of solids will be left behind. Since they were already dissolved in the water to begin with, you know that they must all be water-soluble. Mix them back into water, and they dissolve and turn back into coffee.
Some of the ground coffee does dissolve and some don’t. You can easily tell the difference between fresh and spent coffee as the consistency and color are very different. This is because when you brew coffee you are dissolving the volatile parts of the coffee grounds, such as the caffeine but also color and taste compounds. Instant coffee is made by first brewing regular coffee and then drying it. So all the volatiles in the coffee end up as a powder again. Instant coffee is therefore regular coffee without the spent coffee grounds.
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