I would like to pose a theory for debate. When using a french press I have always been told to decant the coffee right away. The idea is that the liquid coffee is passing back and forth past the filter in the press -therefore over extracting the brew. Is this true?
I recently bought Bodum stainless double walled presses (the Colombian) to reduce breakage and wondered why Bodum made it insulated. Why keep the coffee hot when you are supposed to decant right away into a thermal carafe. I have been casually experimenting not decanting and leaving the coffee in the press. I have not noticed a significant difference in taste, just temperature that obviously changes the flavours. I have noticed that as I pour the coffee out, there are air bubbles under the filter where the spent grounds reside. These bubbles do not go through the filter or move through the grinds at all?! If the air is not getting through the filter how can the coffee?HMMM.... If there is no fluid exchange through the filter is there any over extraction going on I mean really? The only time that there may be some exchange is in the last dregs. If you have the right grind and dose your coffee should me good in the press to the last drop (well almost the last drop).
The pictures are supposed to show the air bubbles right under the filter. Not only are the bubbles not passing through the screen, but they seem to be blocking any other exchange.
Any thoughts?

To see the pictures click on the links below. You may zoom to better view the bubbles.

Views: 5798

Attachments:

Reply to This

Replies to This Discussion

Hi Sam,

I agree that there is probably minimal exchange going on across the filter after you plunge. BUT there is still liquid below the filter. Once you get below a certain level in the press you'll start to drain this liquid too. If you've waited 10 minutes, that liquid has been extracting coffee the whole time. YUM!

I think there's also a sediment issue. There's a layer of fine sediment on the bottom (maybe also on top of the filter too) that you'll want to disturb as little as possible. If you tip to pour, then back up, you'll be disturbing this sediment (as well as forcing an exchange of liquid across the filter). I notice that the brew in your pictures has lots of floaties... I bet if you try to pour gently and in one motion, you won't get nearly that much. Which is the meaning of the term "decanting" - at least in wine.

The process I use is to plunge, then wait 30 sec-1 minute to let some of the silt settle out. Then I pour smoothly off into mugs or a carafe, leaving the last ounce or so of muddy liquid in the press. The cup is a lot cleaner this way. I was amazed at the clarity of flavor that I found once I started minding the mud a bit.

Regarding the insulated Columbia, the real value I see in that is improved temperature stability during brew. I was amazed at the temperature drop that I saw using a naked glass beaker. We now let our presses infuse on top of the espresso machine where its nice and cozy. I have also commissioned some french press "socks" from a friendly knitter.

Hope this makes sense. I'm no press guru, but have tried some tweaks to get the process as good as I can.
One thought, not about the air bubbles, but...

it's a little hard to tell the scale of the photo, but it looks like your grind is too coarse. The coffee looks under-extracted, which would make sense with that grind.

- dc
Don Lundell said:
One thought, not about the air bubbles, but...
it's a little hard to tell the scale of the photo, but it looks like your grind is too coarse. The coffee looks under-extracted, which would make sense with that grind.
- dc
The color depends very much on the roast. I wouldn't say it "looks" week. Does it taste week? Is the ratio correct? That's just something you can't tell from a photograph.

I would venture to say that there actually IS some water flow-through. Not much, but there is definitely enough to over-extract the entire thing if you let it sit for too long. Yes, faster than it would go foul after having been decanted, before anyone asks.

If you don't believe me, try it for yourself.

I like the "mind the mud" approach. I use it myself. I also have another method of getting a cleaner cup that I sort of learned from T. Wendelboe a while back. Brew the press just like you brew a cupping. No floaters. Everything that can sink, will sink. Skim the surface of any floaters and froth. Then put the top on and press.

You have to realize as well that warmer (relative to neighboring molecules) will rise, and relatively cooler molecules will fall. The liquid is constantly moving up and down, changing places until the whole thing cools off to room temperature, and equilibrium is reached.

Decanting is a good idea, I think. I also think that using any approach to get a "cleaner" cup is a positive one, and will result in a longer life of decanted FP brew.

[edit:] I forgot to address the air bubbles. Oil surface tension will hold the pocket of air together. This air pocket is simply too large to pass through the metal mesh filter, and the surface tension afforded by the coffee oils in the immediate vicinity of the grounds prevents it from breaking up.
Couldn't Agree more...Well said!

Brady said:
Hi Sam,

I agree that there is probably minimal exchange going on across the filter after you plunge. BUT there is still liquid below the filter. Once you get below a certain level in the press you'll start to drain this liquid too. If you've waited 10 minutes, that liquid has been extracting coffee the whole time. YUM!

I think there's also a sediment issue. There's a layer of fine sediment on the bottom (maybe also on top of the filter too) that you'll want to disturb as little as possible. If you tip to pour, then back up, you'll be disturbing this sediment (as well as forcing an exchange of liquid across the filter). I notice that the brew in your pictures has lots of floaties... I bet if you try to pour gently and in one motion, you won't get nearly that much. Which is the meaning of the term "decanting" - at least in wine.

The process I use is to plunge, then wait 30 sec-1 minute to let some of the silt settle out. Then I pour smoothly off into mugs or a carafe, leaving the last ounce or so of muddy liquid in the press. The cup is a lot cleaner this way. I was amazed at the clarity of flavor that I found once I started minding the mud a bit.

Regarding the insulated Columbia, the real value I see in that is improved temperature stability during brew. I was amazed at the temperature drop that I saw using a naked glass beaker. We now let our presses infuse on top of the espresso machine where its nice and cozy. I have also commissioned some french press "socks" from a friendly knitter.

Hope this makes sense. I'm no press guru, but have tried some tweaks to get the process as good as I can.

Reply to Discussion

RSS

Barista Exchange Partners

Barista Exchange Friends

Keep Barista Exchange Free

Are you enjoying Barista Exchange? Is it helping you promote your business and helping you network in this great industry? Donate today to keep it free to all members. Supporters can join the "Supporters Group" with a donation. Thanks!

Clicky Web Analytics

© 2024   Created by Matt Milletto.   Powered by

Badges  |  Report an Issue  |  Terms of Service