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Reverse Pour Over
ChicagoJohn
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Posted on 09/22/2016 2:40 AM
After using my new paperless E-PRANCE filter for a while, I decided to try a kind of hybrid method using elements of Aeropress and French press with the pour over paperless filter cone for a yet easier and more repeatable result. The following method will be my morning routine at least for the immediate future -- the best result I've had so far.

I heat 400 ml (~ 13 oz) filtered water in a pyrex measuring cup in our microwave on high for 2 min 30 seconds. This winds up at ~185?F and cools to 175?F for use.

While that is going, I hand-grind three Aeropress scoops (43 gm) of roast blend (2:1 Yirgacheffe : Uganda Mt. Elgon) to a medium-coarse size such as would be used for a French press.

The water is now at 175?F, the optimum Aeropress temperature. I pour 200 ml directly into my mug and put the cone on top in its stand. To the remaining 200 ml in the measuring cup, I pour over my grounds and stir with a fork for 30 seconds. Then I pour this slurry, all at once, into the cone and let it filter down into the 200 ml of water already in there while I rinse out the measuring cup in the sink.

This makes 330 gm of product (11 oz) at the perfect drinking temperature for me, flavor-wise, and it is a noticeable improvement over both the Aeropress and pour over in terms of extraction -- balance of acid / sweetness and a broad palette of coffee flavors, at least to my unedumacated palate. Since I'm pouring the coffee into the water instead of vice-versa, I'm calling it "reverse pour over".

Clean-up is still simple; tap out the grounds residue in the cone into the waste basket and give the cone a quick finger squeegee before rinsing in the sink. I do kind of miss my Aeropress filter papers but c'est la vie; that's what people say....

This is in all respects the best prep method I've found thus far.

(I'm just completing an automated time-temperature data-logger / graphing project for roast profile and instantaneous rate-of-rise using the Arduino Uno with Excel with the Poplite Popcorn Popper mod and will be posting a detailed description and probably a YT video next week. Then I'll start the final step -- adding automated control of the temperature PWM unit to achieve a prescribed curve defined by three input equation parameter values.)
Edited by ChicagoJohn on 09/22/2016 2:47 AM
So many beans; so little time....
 
seedlings
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Posted on 09/22/2016 8:38 AM
Good post John!

I have a similar cone filter, and I tried making standard french press, then pouring into the cone to filter out the fine particles. Filter clogged quickly, and I ended up having french press coffee that day.

They say the 'golden' ratio of water to coffee is 16 parts water to 1 part coffee, by weight. So that's 25g of coffee per 400g water (1ml is supposed to weigh 1g).

CHAD
Roaster: CoffeeAir II 2# DIY air roaster
Grinder: Vintage Grindmaster 500
Brewers: Vintage Cory DCU DCL, Aeropress, Press, Osaka Titanium pourover
 
ChicagoJohn
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Posted on 09/23/2016 6:53 AM
I have never been able to clog my filter, nor have I ever found any evidence of "mud" in the bottom of the cup from small particles getting through it. It consists of an inner, ultrafine mesh stainless steel filter supported by an outer stainless cone with larger but still tiny drain holes in it.

As for the "golden ratio", for me the ideal ratio is what gives me the flavor I'm looking for with the extraction method I'm using, and that depends in large part upon the degree of extraction. That, in turn, depends upon water temperature, residence time, agitation, and particle size / available surface area of the coffee particles.

While I have always begun with the expert recommendations for any process, after benchmarking that result, I tend to systematically explore deviations to see what the effects are and how I respond to them. I started out with the "golden ratio" in my Aeropress and through subsequent experimentation, I found myself going to the higher ratio of coffee I used in my initial post; 1 gm / 10 gm of water; with the lower water temperature, relatively coarse grind, and short residence time as compared with a French press process, and I am only using half of that water to actually extract the coffee; the other half is just for dilution of the extraction. For me, that combination of parameter values, probably resulting in a relatively superficial extraction compensated for, perhaps, with the larger quantity of coffee, produced the ideal blend of flavors and aroma, sweetness versus acidity, and finish.

With the new E-Prance cone, I again started out with the manufacturer's recommendations and what I observed in virtually every You Tube instructional video. After a week or so of this, I went to the method I described and the difference in my appreciation of the result is day and night. That is my criterion and bottom line: It's all about me. The name of the place is "I Like it Like That." roar BBQ grill
Edited by ChicagoJohn on 09/23/2016 6:58 AM
So many beans; so little time....
 
seedlings
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Posted on 09/23/2016 2:10 PM

Quote

ChicagoJohn wrote:

I have never been able to clog my filter


Make a pot of French Press, then pour it into your clean filter. I'm curious if yours will clog or not. Mine clogs from the fines leftover from a french press, but not when used as designed:

https://www.amazo...amp;sr=8-2

CHAD
Roaster: CoffeeAir II 2# DIY air roaster
Grinder: Vintage Grindmaster 500
Brewers: Vintage Cory DCU DCL, Aeropress, Press, Osaka Titanium pourover
 
ChicagoJohn
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Posted on 09/23/2016 5:19 PM

Quote


Make a pot of French Press, then pour it into your clean filter. I'm curious if yours will clog or not. Mine clogs from the fines leftover from a french press, but not when used as designed:

https://www.amazo...amp;sr=8-2

CHAD


While your filter looks much like mine, it does say "titanium coated", and that probably means PVD - physical vapor deposition. They would do this to improve surface hardness. I'm somewhat familiar with this process and it involves vaporizing a metal, such as titanium, chrome, copper, aluminum, etc. in a vacuum chamber (to prevent oxidation) with the cooler substrate in contact with that vapor so as to promote condensation on its surface. Such coatings are very thin, measurable in angstrom units, however, they are not nice flat, smooth films or plates; under high magnification, they look like stalks of grass. So it is possible that such a surface could be more prone to entrapment of very small fines from a grinder, especially if the grinder has worn burrs, or if it were a blade grinder, or if for any other reason it tended to produce high levels of fines.

Why it would not do this if the grounds were added to it for a pour over, is that the grounds themselves act like a filter preventing mobility of the fines through the bed. But if the slurry is poured into the cone after it is put into suspension and then allowed to stand for awhile (and especially after pressing the French press plunger down trapping all of the coarse particles under it, then the first liquid entering the cone filter will have a highly elevated level of the finest fines. This is because the larger ground particles have a faster settling rate while the fines have a very slow settling rate. Four minutes in a French press is a long time to settle and that is accentuated by activating the plunger.

Back again to the grinder; I am using a little hand grinder set on a medium to coarse grind and I am getting very few fines (although I know it is fully capable of making levels of fineness surpassing the espresso grind my wife buys from Charbucks). Before I dig my French press out to experiment, just for you tomorrow morning I will allow my slurry to stand for four minutes and then carefully decant most of it into my cone filter and use a silicone spatula to scrape out the rest at the end and we'll see if that clogs it.

Even if it doesn't, however, it still could be either a difference in level of fines in your grind versus mine and/or the titanium coating on your screen (which could affect retention of tiny grind particles).

What I would ask you to try is the exact method I described; viz., use a coarse grind, vigorously mix the slurry and dump it into the cone filter all at once. I bet it won't plug up if you do it that way, and I'll see how much extra bitterness and astringency I acquire with the longer soak time. Shock
So many beans; so little time....
 
ChicagoJohn
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Posted on 09/24/2016 3:51 AM

Quote


Make a pot of French Press, then pour it into your clean filter. I'm curious if yours will clog or not.


Short answer - It clogged. I used my std 42 gm of beans ground to my standard grind, dispersed the grind in 200 ml hot water, setting aside the other 200 ml, then I let the slurry stand for 3.5 minutes (4 min total including 30 sec agitation).

The great majority of solids had settled. I carefully poured the supernatant liquid slurry onto the filter making sure to include the sides sufficiently and after it was all in there, I then added a little more water to the remaining solids and put that in, but by the time I had done that, the filter was already plugged and the existing liquid was just sitting there with the occasional drop dripping off the end of the cone.

I tried drinking this but it was way too over extracted for me and left a raging astringent finish that lingered for what seemed like an eternity. So I had to dump that out, but it's all good -- in the interest of science, etc.

My second brew was made my new standard way, just as above but with immediate dumping after the 30 second stir, and as anticipated, no clogging and what I consider to be my perfect cup (so far).

So I decided to try one more experiment. I transferred everything I could get out of the filter into another container, added 200 gm of water, stirred it thoroughly and let it stand four minutes. When I poured the supernatant liquid over the filter surface, it clogged again.

These observations would seem to be consistent with the mental model of differential settling rates resulting in particle size segregation such that the supernatant liquid is superfine rich and this high concentration of fines contacting the filter openings causes it to clog. When the particle size distribution in the liquid more closely reflects that of the dry grind via an immediate pour after agitation, then the particles of the grind act as a filter to retard the movement of fines through the filter cake thus reducing the incidence of contact of fines with the filter openings.

While I do not have a refractometer, this morning's observations also confirm my suspicion that presently my preferences lie in the direction of a relatively strong cup but one that is composed of lower extraction levels. In other words, maybe the four minute soak would have been up over 20% extraction whereas the 30 second agitation perhaps 15-17%, but since I have a significantly higher coffee-to-water ratio than one normally would for a drip or pour-over process, the strength of the product is still reasonably high. Its composition is, however, shifted in a direction that suites my taste.

Since my wife has an espresso machine, when I run out of other things to do, I may start playing around with that and I'm sure it will be starting over from square one.

Anyway, it's not the titanium coating; regardless of whether it is PVD titanium or an organic titanate, used to deposit a monomolecular layer of Ti-O on the surface to dramatically increase wetting tension as these are typically used in paint primers. I would doubt it's that, though, because these would be subject to erosion over time whereas as PVD titanium would be more durable and could also impart improved surface energy characteristics.

Speaking of which, by the way, I've found it helpful to periodically immerse my filter in a container of water that as a couple drops of dish washing detergent dissolved in it. This dramatically improves flow rate through the filter which can, over many uses, develop a more hydrophobic surface, presumably from deposition of various oily compounds coming out of the coffee. I just push it down letting it reverse-flow fill the cone then lift it up to drain and do that several times before thoroughly rinsing and soaking in plain filtered water to remove the last vestiges of surfactant.

Let me know if you should decide to try the reverse pour-over as I've described it whether or not you still see clogging.
So many beans; so little time....
 
seedlings
Top  #7 Print Post
Posted on 09/25/2016 2:22 PM
I will roast some coffee, and try your Aeropress hybrid slurry positive this afternoon!

CHAD
Roaster: CoffeeAir II 2# DIY air roaster
Grinder: Vintage Grindmaster 500
Brewers: Vintage Cory DCU DCL, Aeropress, Press, Osaka Titanium pourover
 
seedlings
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Posted on 09/25/2016 3:27 PM
Followed your measurements exactly, except I measured grams of water instead of ml.

Since I literally just pulled this Sidamo out of the roaster (11 min roast to 425F), it tastes just a little thin or weak to me, but the ratio of water to coffee is fine (18:1 roughly).

I really like the idea that the coffee steeps for a time. The French press is the ideal brewing method if only it could be as clean in the cup as these mesh filters. Your method is a great workaround. My filter did start dripping slower, evidence it would have clogged with any larger amount of slurry.

CHAD

**Edit:. Rereading your posts, I missed the 'coarse grind' direction, and ground like table salt, as I do for Aeropress and this titanium filter.
Roaster: CoffeeAir II 2# DIY air roaster
Grinder: Vintage Grindmaster 500
Brewers: Vintage Cory DCU DCL, Aeropress, Press, Osaka Titanium pourover
 
ChicagoJohn
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Posted on 09/25/2016 4:05 PM

Quote

seedlings wrote:

Followed your measurements exactly, except I measured grams of water instead of ml.

Since I literally just pulled this Sidamo out of the roaster (11 min roast to 425F), it tastes just a little thin or weak to me, but the ratio of water to coffee is fine (18:1 roughly).

I really like the idea that the coffee steeps for a time. The French press is the ideal brewing method if only it could be as clean in the cup as these mesh filters. Your method is a great workaround. My filter did start dripping slower, evidence it would have clogged with any larger amount of slurry.

CHAD


I'm so glad you had an opportunity to try it. Of course your decision to use grams is much more accurate and repeatable than measuring milliliters in a measuring cup, and grams and ml are the same; exactly the same at 4?C, where water's density is highest, and the deviation due to thermal expansion between 4 and 23?C is beyond measurement error for any available scale anyway.

After I pour off 200 of the 400 ml and add my 42 gm of grounds, stirring with a fork fairly vigorously for 30 seconds and then dumping the slurry as rapidly as possible into the cone situated over the 200 ml of hot water in my cup, I've found that it takes 105 seconds before the steady stream of coffee ceases and starts dripping. (This would not include the few seconds it takes me to put down the measuring cup and start my timer). As soon as the steady stream stops, I move the cone off my cup and I'm done to another to finish draining, but after that only six more grams eventually drips out anyway.

So if you should try this again, you might see how long the steady stream persists for your set up. If it is significantly shorter, and if a lot more eventually drips out after the steady stream stops and you transfer the cone to an empty cup, that would suggest one or more of several possible differences including particle size distribution, filter pore size, effects of the titanium surface treatment, among others. I would be an interesting addition point of comparison.

What I like about this method is something it has in common with the Aeropress; viz., that every grounds particle sees roughly the same aqueous environment for approximately the same amount of time before the separation process begins. In my mind that is preferable to the variation grounds in a pour-over process may be subject to by virtue of their location in the bed and how the water is poured. Obviously the grounds on the top will be extracted by pure water whereas those on the bottom would be extracted by water with a lot of coffee compounds already dissolved in it. Then you have the issue of the sides, temperature gradients and so on. I always stirred my Aeropress for 10 seconds before pressing, and this is pretty much the same thing -- the amount of agitation time, like water temperature and quantity would be parameters that could be explored for optimization.
So many beans; so little time....
 
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