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After my instant coffee (with chicory mix) powder got hard due to moisture I decided to heat the hardened coffee in a pan, and it got soft stuck to the pan like chocolate, and even had strings when I broke it (something like when you pull a caramel bar). I expect it to form a powder on heating, instead of turning into candy. Was it because of the water content?

Glorfindel
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dl12
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1 Answers1

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This also happens with common unsweetened instant coffee (without chicory) if you allow it to cake and then try to heat in a pan or any other kind of heat that is concentrated on a specific spot or surface.

Instant coffee (a.k.a. soluble coffee) is made by spray-drying brewed coffee, and not by finely grinding coffee grains. You are not dealing with a moist powder that can be dried by local application of heat, like when you have wet flour or wet coffee grounds.

The coffee was partially dissolved by the moisture but it lacks the crystalline quality of other solutions that naturally form grains or crystals - like salt or sugar - it then becomes an amorphous mass and when you try to heat it up, it melts instead of crystalizing. This will also happen if you try to heat it up in the oven.

You can still use it as is - it will take longer to dissolve and need more stirring than you usual powder. The only way to fully recover it is to replicate the process used to make it - re-dissolve it and spray-dry (which is very difficult to do in a domestic setting)

Juliana Karasawa Souza
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    That's really interesting! – GdD Oct 30 '19 at 14:12
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    This is also why instant coffee dissolves. If they are using actual coffee grounds, you will be drinking some very rough coffee... – Nelson Oct 31 '19 at 03:02
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    Very interesting! It sent me off researching "spray drying", it's worthwhile mentioning that instant coffee could also be freeze-dried: https://www.healthline.com/nutrition/instant-coffee-good-or-bad – Alex KeySmith Oct 31 '19 at 11:18
  • Could you just grind it up to get something close to the original products usability without having to invest in spray/freeze drying tools, or would it just gum up the grinder? – Dan Is Fiddling By Firelight Oct 31 '19 at 13:30
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    Would probably just gum up the grinder. Use hot water to get it away from something it's stuck to. – Gloweye Oct 31 '19 at 14:36
  • @DanNeely I don't even think that there is a domestic scale spray / freeze dryer. The smallest ones I've ever seen for R&D applications are the size of a big fridge. – Juliana Karasawa Souza Oct 31 '19 at 16:58
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    @Dan: I'd consider freezing it really hard and hand grinding it with a grater or microplane, ideally onto a cold metal pan/sheet. Just an idea though. – nomen Nov 01 '19 at 15:37