Under extraction and over filtering

My coffee business has been growing (slowly)! Yay! :-?
Up until now, I have been hand-crafting cups of coffee using either single-cup Bonavita immersion drippers (with swiss gold filters) or large French presses.
I always leave coffee & water together for 4 minutes prior to serving.
The cups of coffee are great and my customers think so too.

I have recently bought a Bunn CW15-APS with "gourmet C" funnel because I have reached the limits of how much coffee I can hand-craft.
In experimenting with this device, I have been using an identical ratio of coffee to water as I previously has success with.
This amounted to precisely what Bunn recommends anyway, which is 3.5 oz coffee to 64 fl oz water.
The coffee tastes significantly weaker than my hand-crafted cups.
I think this is because I cannot control the amount of time the coffee and water stay together before the finished product pours out of the bottom of the (huge IMHO) hole in the funnel.
Another possible factor contributing to the disappointing result is the usage of a paper filter, which filters out the grounds better, but also filters out the oils too.
I am trying various things to delay the liquid before it exits the funnel.
I have tried to partially block the exit hole in the funnel. I wasn't too successful at this. Looking at the paper filter afterwards, I can see the liquid level inside the funnel didn't rise very high at all.
I have tried using 10% more coffee without much difference. I find this a somewhat wasteful direction to head in.
I will try more things to slow up the liquid flow (my wife suggesting using two paper filters).

So my questions to wiser folks on this forum is:
1. Anyone got any suggestions as to how to improve extraction?
2. Is there the equivalent of a swiss gold filter for a Bunn Gourmet C funnel?

Thanks in advance for your help.
 

Musicphan

Active member
May 11, 2014
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Kansas City
Your coffee/water ratio appear to be correct... I use 110g for 64 ounces of water using a Bunn VPR-APS (essentially same brewer). I would say it's makes a solid cup of coffee but not as rich as a pour over. Do you have TDS meter to see if it's extracting properly or just perception? Have you played around with your grind? I would not think that a diff filter or gold filter would make a significant difference.
 
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NorthSouth

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Feb 13, 2012
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North East North Carolina, USA
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Thanks for your response.

Indeed I do have a TDS meter. Doh! I didn't think to use it. Good suggestion.
I will try that tomorrow morning for both the Bunn & the Bonavita.
I will also try a finer grind (Bunn only).

At one try per day all this will take a while - I can only drink so much coffee and I don't want to inflict my experiments upon my customers.

The difference between paper and the swiss gold filters in the Bonavita is very obvious from a taste perspective.
It is also visually obvious when you see the oil on the top and the mud in the bottom of the cup, both of which the swiss gold filter allowed to pass.
That's the reason I am curious as to whether someone makes a non-paper filter for the Gourmet C funnel.
 

Musicphan

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May 11, 2014
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Kansas City
Yes... you will want to run a bit finer for your Bunn vs. Bonavita's... and no matter what you will get a different brew out of your Bunn simply due to the fact it's not a immersion brewer. The immersion brewers simply extract a bit more due to the constant contact with the ground coffee. Regarding the taste of the filters.. typically what you are noticing is a difference in extraction because the gold filters allow more dissolved solids to pass through them because they are more porous. Net-net... you will never get the exact same flavor profile out of the two.. Just keep trying :)
 

John P

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Jan 5, 2007
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Salt Lake City
55-60g/Liter is the correct range. You might try adjusting you grind.

While this might not sound helpful, it really is... If you are trying to augment your "hand-crafted" coffee by introducing a higher volume brewer, using that particular brewer does not make a lot of sense.


Curtis (or Fectco) make the best brewers out there. Curtis is probably a bit better.
While from a positioning and marketing standpoint it is counter productive to offer both types (hand and batch) of brewing... happy to discuss why if you haven't thought this through... if you are looking for the best brewer for batch brewed coffee, it would be this - (While the price point is a bit higher for this brewer, the results justify it.) In the scheme of things, it's nickels and dimes.

https://www.seattlecoffeegear.com/curtis-tp15s-single-airpot-brewer

 
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NorthSouth

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Feb 13, 2012
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North East North Carolina, USA
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I would really like a Fetco brewer.
Unfortunately, they don't make (as far as I know) a brewer that isn't plumbed in.
I do markets and private functions and must be able to move my equipment.
Not plumbed machines really narrowed down my choices :cry:

I haven't heard good things about Curtis.

Thanks for the suggestions.
 
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