Okay - so first things first. Im going to apologize now for the less than stellar photography in this post. Everything was done in a bit of a rush and I can see that its going to require a bit more thought and maybe even breaking out my 'real' camera. These coffee posts are going to be..on going - so it will be fun to see the evolution of the photograph...I guess.
So a friend and I have been randomly bullshitting about coffee and fun ways of brewing it (stemming from him having some ordeal with a broken burr grinder and a coffee snob, and me then talking about the old silex that was found in my attic). So fast forward a bit and I was sitting around thinking about making some desserts and how I have yet to use my iSi canister that Ive had for about a year...and I remember reading about how you can make instant infusions with the iSi canister. For some reason the first thing that came to mind was coffee...and then I was off, in the bowels of the internet, trying to find any information I could possibly come up with. And there was a couple sites that had talked about playing with it. And I mean a couple...as in two. Im sure theres more but my googling skills are only so-so.
Anyway, in the time I spent searching for information on what I will now refer to as the "n2o brew" I came across about a million other variables that people take into consideration when brewing coffee and some pretty interesting ideas on how to get the perfect cup.
Im rambling now. Time to get down to business. Ive decided to pursue a better cup of coffee - no matter how impractical it is. And because of the lack of information out there (or at least the lack of information-that-greg-can-find-quickly) I am going to document my results on here. Because theres a lot of really long brew times, I only have one iSi canister, etc.. these wont be very...scientific, but I will do my best to document everything and be as consistent about things as possible. So here goes (and please remember my disclaimer about the photos!)
Brew: n2o in 1 liter canister
Room Temperature: 24.4 C
Grinds: 31.8 g, room temperature
Water: 510.29 g tap, filtered through a Brita, room temperature
Brew Time: 15 h 24m in fridge
So I simply put room temperature water and grinds in the canister, charged it twice and tossed it in the fridge for 15 hours & 24 minutes. Today, when I was going to taste the n2o brew, I also poured a hot cup of coffee made in my KRUPS automatic drip with the same ratio and ingredients. This is more-or-less what I have every day. I also took a cup of the n2o brew and poured it between two cups 20 times to aerate it a bit (just like you would with wine. Sadly I do not have one of those wine aerators so instead I made a huge mess). This gave me three different cups to taste (aerated n2o cold brew, n2o cold brew, automatic hot brew)
What you see above is the n2o cold brew on the left, and the automatic hot brew on the right. Its a bit hard to tell, but the n20 brew is a lighter color and cloudier than the hot brew.
There was also a noticeable amount of oils on the surface of the n2o brew - did my best to capture these with my iPhone.
Versus the complete lack of oils on the surface of the hot brew.
I was having a hard time capture the colors with my phone so I put all three brews into pipettes. From the top down you have the aerated n20 cold brew, the n20 cold brew, and the automatic hot brew. As you can see there is virtually no difference in color between the two n2o brews and the hot brew is noticeably darker.
|L-R: Aerated n2o, n2o, hot automatic drip|
So...my results. The two n2o cups were very similar - Im not sure how effective my aerating process was but I do think that the aerated cup was the most enjoyable - same flavor profiles as the plain n2o but not quite as in your face. Both n2o cups were very sweet (everything was unsweetened and black) up front and then mellowed into a somewhat complex, roasty flavor. Definitely good coffee. Now for what was most shocking to me - the hot brew, which I mentioned I have been drinking daily, was practically undrinkable by comparison. The flavor was completely different - if this was a blind test I would not have believed they were made from the same bean.
So my conclusion - Aerating the coffee helps soften the flavors, n2o cold brew is tasty - but is it tastier than a normal cold brew? And I cannot believe how bad my normal coffee is.