I did the vacuum coffee project from the latest issue. Two problems I wondered if you all had, and if you all know how to solve:
1. coffee comes out VERY thin. I was hoping it would be very stout. I believe I can solve this by allowing the fire to continue to burn for longer, thus allowing longer extraction. 2. It comes out lukewarm...which is a "duh!" because the flask has to cool to draw the vacuum. Anyone figured a way to have the coffee hot and sucked back too?
I've had a go at it. I picked up what I needed locally yesterday and assembled everything this morning. Unfortunately I broke my boiling flask on the first full run. :( I had 2-3 practice "brews" with just water and every thing worked fine. I suppose I got too aggressive with the heat.
I wish I'd have purchased more than 1 Florence flask now.
As for the temp on mine the water was steaming nicely in the Griffin flask on my practice runs but I never actually checked the temp after it siphoned back to the boiling flask. I have noted at coffee shops that espresso is not very "hot".
As for weak brew, you could try maintaining a low boil in the flask longer to add to the time that the grind steeps in the beaker. That should help. Also, experiment with finer grind and of course more grind may help too.
Yep, I thought about that too. I'm hunting around now for a boiling flask with a mouth large enough to hold the thistle funnel.
Then, I"ll put the funnel and the coffee in this flask, along with a cork. Cork will have second hole. Second hole will run back to flask #3 via glass tube. Flask 3 will then be used to pressurize the extraction flask during the collection phase. I.e., Boiling flask 3 will "blow" while boiling flask 1 "sucks". This way I can control heat, time, and extraction.
Doc, thanks for suggesting keeping the flame on the florence flask a bit longer to increase brew time. That's what I did. Same goes for dialing in your grind and dose. LOL'd about your gas torch!
jg0801, That sounds very interesting, please let me know if you pursue that method. -John
I rigged propane tank and hose to my bunsen burner and that works good for the heat source now. The MAPP gas torch was serious overkill!
I managed a good test run this AM using a paper filter. Worked fine in a double layer and tied with cotton string. I brewed with used grind from this mornings pot so it was weak but the filter held up fine. Previous tests with single layers would split open and let grounds through. Also I pushed the filter about 1-2cm into the thistle funnel and then secured with the string.
Here's a link to the only picture I have - I'll try to get one of the filter setup of you'd like.
Doc, I'm so excited to see evidence that someone built one of my projects in the wild! Very nicely done. What sort of brew time are you targeting? I haven't tried paper filters, but I'm very happy with the cloth one I've been using over and over again. -John
I tried the paper filter because I didn't think to order the Yama clothe filter ahead of time. I don't know how long the paper filter will hold up, but it has survived to brewings so far. *grin*
I steeped for about 90 seconds and I could taste a hint of bitterness. I'll try 60 seconds next time.
I ordered my supplies from a lab supply place in Denver and they cost my $130 including some clamps and an extra funnel I didn't end up using.
Not including the burner and propane. I got a cheap burner at the store. It's similar to the one in the coffee roaster plan (where I got my inspiration for using it.) Of Course I took it apart before I ever even tried it. That's why my burner is just the ring.
I ran into a small problem when I snapped one of my glass tubes while trying to bend it. I didn't get it hot enough and I was putting too much pressure on it to detect when it got soft. I only lost about 4 inches worth of glass pipe. Because my burner is so tall, I had to put my mixing vessel on a stand. I used the box my burner came in.
I just used an ordinary funnel with a 6mm stem and wraped some coarse cloth around it and sealed it with some thread.
When I fired it up, I was a tiny bit worried because I could hear some glass pinging type noises.
Things I wish I had done differently:
1. I should have got lots more glass tubes, and maybe longer ones. 2. I should have got a flat stand for the mixing vessel. 3. Cleaned up the background before the maiden brewing.
Things that were harder than I thought they would be:
1. Finding glycerin. (it's in a little brown bottle in the first aid or ear care section of the bigger stores). 2. Taking it apart to clean. The tube is hard to get in and out of the stopper, even with lots of glycerine. 3. REI didn't have the single burner, but Fred Meyer had a cheap one.
Things I want to do next:
1. Get longer glass tubes and bend them in such a way that I only need one stand. That way I can put the mixing vessel on the table and save my other stand for another project.
2. Replace the stand with something made of etched brass to give it a real steam-punk look.
Oh, and the coffee was very smooth. It didn't make dark thick slightly sludgy coffee like the french press. It was almost like tea in a way. Very drinkable. I had to save most of it in my thermos for the morning so I won't be up all night.