What makes coffee grinds sink in a french press?
We use a press pot to make coffee at home, and usually after a 3 minute steep, the grounds are floating at the top, but with this one bag of beans we got, they're all sunk to the bottom.
The coffee basically tastes normal. Maybe a little thin, but that could easily be the roast.
Why would most coffee grounds float, but these sink? Is there something wrong with these beans?
We use a burr grinder and hadn't changed the grind setting. Same water, etc. Only change is the beans. "Medium-Dark" roasted Ethiopian Yirgacheffe from a local roaster, roasted about 2 weeks before brewing...
Best Answer
The question should really read "What makes coffee sink?" It does not matter if it is in the form of grinds or beans (though it is easier with grinds) nor does the receptacle. The issue is buoyancy.
buoy·an·cy (boin-s, byn-) n. 1. a. The tendency or capacity to remain afloat in a liquid or rise in air or gas. b. The upward force that a fluid exerts on an object less dense than itself.
As the coffee is soaked in the hot water chemicals are extracted from the grind, mostly oils, that have an impact the buoyancy of the coffee. Once, the desirable chemicals are extracted to the surrounding water (again, moistly an oil) the buoyancy of the coffee is altered and the residue sinks to the bottom.
During my time in the U.S. Army field coffee was made quickly by getting a 15 gallon stock pot boiling and just pouring a five pound can of coffee in. Allow to boil for 5 minutes, reduce the heat and hit the side the stock pot with a ladle. Immediately all (ok, most...) of the coffee would sink to the bottom and fresh (if not altogether worthy of Starbucks) coffee could be ladled out. Why whack the pot? This would disrupt boiling of the water and allow the coffee to sink quickly.
Why are your grinds sinking? Well, the best guess is that they came deficient in the compounds that make the coffee normally buoyant. If the brand/roast is not up to your satisfaction you should be able to return it for fresh. If this a brand to which you are accustomed, but this batch isn't 'normal' then it is probably an anomaly, as you said the coffee tastes normal, so I wouldn't not worry to much about it.
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Quick Answer about "What makes coffee grinds sink in a french press?"
As the coffee is soaked in the hot water chemicals are extracted from the grind, mostly oils, that have an impact the buoyancy of the coffee. Once, the desirable chemicals are extracted to the surrounding water (again, moistly an oil) the buoyancy of the coffee is altered and the residue sinks to the bottom.Should coffee float in a French press?
You want the coffee swimming happily in the water, not floating on top. That's what the second stir is for. Not all coffees will create a big crust. Some high-altitude beans release very little air and the grounds are heavier, so you won't see an exaggerated crust.Why do some coffee grounds float?
Coffee grounds, buoyed by gases formed in roasting, float when hot water is added, while tea leaves immediately get wet and sink.How do you keep coffee from coming down the sink?
Swiftly turn the brewing chamber upside down on top of the strainer. This way you will run all the grounds and the water through it and prevent the coffee grounds from going down the drain.Why does my French press leak grounds?
The main problems from a French press usually come from either your grind being the wrong size, or you're plunging too hard. Or you could have a broken French press, here's how to check and make sure you're getting your coffee right.Coffee grinds in a French press, no disposal.
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Answer 2
Coffee beans contain gases, which causes coffee to float.
Fresh coffee contains more gases compared to an older (aged) coffee.
- coffee tastes best between 4 - 14 days off roast, varies depending on roast profiles
- Specialty coffee shops usually have a roast date on their retail bags
On a coarse grind setting each particle hold more gases compared to a fine grind setting which hold less gases.
Hot water causes a faster release of gases compared to cold water which causes a slower release of gasses
Darker roasts hold less gases compared to a lighter roast.
A lot of agitation increases the rate in which gasses release compared to no agitation.
All these can be easily tested, and affect how long the coffee stays afloat.
Gasses in the coffee particles must first be displaced in order for the water to enter each particle and extract a delicious cup. All in all, it doesn't matter why, as long as the coffee tastes good.
Late reply but thought I'd clarify.
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