Brewing Coffee in a vacuum??


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Jun 24, 2019
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Hi, I'm new to the forum and fairly new to Coffee brewing. Does anyone know the science behind what happens if you hot brew coffee in a vacuum and if its beneficial in adding anything to brewing coffee? I searched the internet and all I could find info on was the siphon vacuum two chamber brewers, but those aren't really brewing coffee in a true vacuum. They are really just using vapor pressure to force the coffee up into a chamber above.

I bought some vacuum Mason jar lids from Amazon and have been experimenting using them to brew.

I boil water, then put ground coffee into the jar, then add the boiling water, then put the lid on and use the pump to suck all the air out to make a vacuum. I let it sit for 4 minutes, then I pour off the coffee into a glass to drink. I don't use any filter because the grains mostly settle to the bottom and the pour off is to my liking for drinking.

I'm going to do some side by side testing soon, but for now it seems to make a really nice cup of coffee and I don't notice any bitterness, but that could be because of may variables. I do notice that when suck the air out of the jar to make a vacuum, a bunch of air bubbles shoot up through the coffee water and the liquid almost instantaneously turns dark as if the vacuum is rapidly sucking/extracting everything out from the grounds. It makes me curious if it would be better to cut the extraction time way down, and also I'm wondering if more caffeine will be extracted,etc.

Anyway, I'm going to experiment using different extraction times, as well as using diffent coffee amounts, grinds, water temps, etc. Has anyone else done this, and as stated above, does anyone know the science behind what's happening here?
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I have no real expertise in this area... but from my understanding when brewing under vacuum it's creating a slight agitation of the coffee although it's not visible. It seems to me that Scott Rao did some testing on this theory... you may want to check out his blog/Instagram. There is a new brewer that was released at SCA - it combines pressure and agitation for fast brewing - it may be of interest to you.
James, there are a number of coffee brew systems, some from the late 1800's that are called "vacuum brew", but in fact they are a siphon system that were amazing designs for their time. It is still my personal favorite way to make coffee. Nicro Vacuum Coffee Maker.jpg This is my Nicro 500 all stainless steel brew pot. I have many types from very old to about the 1950. The amazing part is how well these units hold the water temp. The coffee is exposed to perfect 205°F water. Once the water travels to the upper chamber and the pot is taken off of heat, within seconds the lower chamber will start siphoning the brew past a stainless steel filter. The results are the smoothest coffee with no bitterness. Perfect coffee!

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