Our Valued Sponsor
OpinionsConsumer ReviewsGuides and How TosCoffeeGeek ReviewsResourcesForums
Coffee: Questions and Answers
.
Rancilio Silvia - How to
Step by step guide for easy brewing and steaming with the Rancilio Silvia
www.seattlecoffeegear.com
 
Not Logged in: Log In to Postlog in
New Topics updated topics   New Posts new posts   Unanswered Posts new unanswered  
Search Discussion Board search   Discussion Board FAQ faq   Signup sign up  
Discussions > Coffee > Q and A > .  
view previous topic | view next topic | view all topics
showing page 10 of 14 first page | last page previous page | next page
Author Messages
jpender
Senior Member
jpender
Joined: 11 Jul 2011
Posts: 708
Location: California
Expertise: I like coffee

Grinder: OE LIDO
Vac Pot: S/S Moka Pot
Drip: Aeropress
Posted Mon Jun 4, 2012, 2:51pm
Subject: Re: Coffee Extraction Discussion, Questions for the membership:
 

Netphilosopher Said:

The latest folly I think may answer the question of "what's left in the puck?"

I thought that if I brewed some coffee with immersion method (inverted AeroPress), then run a 2nd stage "rinse" of the wet grounds with known amount of water, I may be able to tease out roughly how much of the dissolved TDS is in solution vs. how much is just not removable due to the absorption of the grounds.

Posted June 4, 2012 link

I tried this in February.

You may have missed my post on it. I didn't include details because it appeared at the time that rinsing with cold water extracted a large amount of additional solids making the experiment useless. Well if you missed that it's probably just as well because when I went back just now to see why my results differed so much from yours I discovered I'd made an error. When I corrected for that I got something in the same ballpark as you did. Not exactly the same but the measurement error wasn't small. Basically, I had diluted by about 20 to 1 and the second press extracted about 2/3 as much as your original hypothesis predicted (with emphasis on "about").
back to top
 View Profile Link to this post
jpender
Senior Member
jpender
Joined: 11 Jul 2011
Posts: 708
Location: California
Expertise: I like coffee

Grinder: OE LIDO
Vac Pot: S/S Moka Pot
Drip: Aeropress
Posted Mon Jun 4, 2012, 2:59pm
Subject: Re: Coffee Extraction Discussion, Questions for the membership:
 

Netphilosopher Said:

Nope you're not misunderstanding it at all.  VST/mojo is NOT an EXTRACTION measurement device.  It measures %TDS - in fact, that's ALL it measures (internally, it measures refractive index of a filtered liquid, and then converts and reports this in %TDS - but it does not display the actual nD).

As far as I know, there really is no way to measure "extraction" per se directly - everything is by measured inference.  Either you're keeping track of solids transferred to the beverage, or you're backcalculating from strength.

Moka - just use the solids yield.  That's as accurate as it gets, since it's a wash method (forced percolation).  How much coffee did you use?  How much coffee beverage did you produce?  What's the strength of the beverage?

E = S Cp/C
where E=Extraction
S=Strength
Cp=Coffee Produced
C=Initial Dry Ground Coffee

Posted June 4, 2012 link

But the strength is dissolved solids concentration. Solids yield is a measure of total solids. So how does mojo start with a measure of dissolved solids and determine total solids like on Andy Schecter's espresso control chart?

That's my confusion.
back to top
 View Profile Link to this post
GlennV
Senior Member


Joined: 27 Oct 2011
Posts: 29
Location: UK
Expertise: I love coffee

Posted Mon Jun 4, 2012, 3:35pm
Subject: Re: Coffee Extraction Discussion, Questions for the membership:
 

.
back to top
 View Profile Link to this post
andys
Senior Member
andys
Joined: 10 May 2003
Posts: 857
Location: NY
Expertise: Just starting

Espresso: Speedster, Londinium 1
Grinder: EK-43,Robur, HG One, M3
Vac Pot: Yama
Drip: various
Roaster: PIDed Popper
Posted Mon Jun 4, 2012, 5:44pm
Subject: Re: Coffee Extraction Discussion, Questions for the membership:
 

jpender Said:

But the strength is dissolved solids concentration. Solids yield is a measure of total solids. So how does mojo start with a measure of dissolved solids and determine total solids like on Andy Schecter's espresso control chart?

Posted June 4, 2012 link

You're right, the espresso "control chart" that I posted on Home-Barista was based on Total Brew Solids (dissolved and undissolved) rather than Total Dissolved Solids. Subsequently, testing by Vince, the Terroir folks, and others suggested that TDS correlated better with flavor balance than did TBS. So ExtractMoJo and Mojotogo are based solely on TDS.

 
-AndyS
picture page:  http://flickr.com/photos/andy_s/sets/
back to top
 View Profile Visit website Link to this post
GlennV
Senior Member


Joined: 27 Oct 2011
Posts: 29
Location: UK
Expertise: I love coffee

Posted Tue Jun 5, 2012, 2:56am
Subject: Re: Coffee Extraction Discussion, Questions for the membership:
 

OK, according to experiments reported in

"Role of Water State and Mobility on the Antiplasticization of Green and Roasted Coffee Beans"
Pietro Rocculi, Giampiero Sacchetti, Luca Venturi, Mauro Cremonini, Marco Dalla Rosa, and Paola Pittia
Journal of Agricultural and Food Chemistry 2011 59 (15), 8265-8271  (page 8269)

roasted coffee beans can hold about 20% by weight of "unfreezable water", "(usually considered as water bound to the macromolecular matrix with a mobility so limited that it cannot freeze)". This is at the upper end of previous results they reference.

That's 20% water and 80% dry coffee - so 0.25g water/g dry coffee!

This is at equilibrium. I don't think grinding would change things much apart from the time to equilibrium. Anyway, that's good enough for me for now.

It's a pity, I think, that David Walsh's big study hasn't asked contributors to record brew method - as this might have revealed a preference for different yields with different methods whenever a blanket 2g water/g dry coffee is used.

Thanks Netphilsopher - here's looking forward to more results on grind size, temperature and time!
back to top
 View Profile Link to this post
Netphilosopher
Senior Member


Joined: 14 Jan 2011
Posts: 1,602
Location: USA
Expertise: Just starting

Posted Tue Jun 5, 2012, 4:29am
Subject: .
 

.
back to top
 View Profile Link to this post
Netphilosopher
Senior Member


Joined: 14 Jan 2011
Posts: 1,602
Location: USA
Expertise: Just starting

Posted Tue Jun 5, 2012, 5:13am
Subject: .
 

...
back to top
 View Profile Link to this post
jpender
Senior Member
jpender
Joined: 11 Jul 2011
Posts: 708
Location: California
Expertise: I like coffee

Grinder: OE LIDO
Vac Pot: S/S Moka Pot
Drip: Aeropress
Posted Tue Jun 5, 2012, 11:45am
Subject: Re: Coffee Extraction Discussion, Questions for the membership:
 

andys Said:

You're right, the espresso "control chart" that I posted on Home-Barista was based on Total Brew Solids (dissolved and undissolved) rather than Total Dissolved Solids. Subsequently, testing by Vince, the Terroir folks, and others suggested that TDS correlated better with flavor balance than did TBS. So ExtractMoJo and Mojotogo are based solely on TDS.

Posted June 4, 2012 link

Andy, thank you for the clarification.

According to Illy the total solids in espresso are typically 90% soluble. So a target soluble extraction of 18-21% would imply a solids yield of about 20-23%. Does that mean further testing showed that the following line from that Home-Barista post turned out to be not quite true?

For instance, rather predictably, espresso extracted on the low side of solids yield (say 15-16%) tastes sour for many light-roasted coffees and "green" for many darker-roasted coffees. Espresso extracted on the high side (say 20-23%) begins to taste harsh or bitter.

back to top
 View Profile Link to this post
jpender
Senior Member
jpender
Joined: 11 Jul 2011
Posts: 708
Location: California
Expertise: I like coffee

Grinder: OE LIDO
Vac Pot: S/S Moka Pot
Drip: Aeropress
Posted Tue Jun 5, 2012, 11:49am
Subject: Re: Coffee Extraction Discussion, Questions for the membership:
 

Netphilosopher Said:

-Surprisingly, cone filtration through a Melitta filter works pretty well.  Less so if you filter the coffee only, better if you dump the slurry into the cone.  I think this is helped by "cake filtration" of the grounds, but there's the initial amount of the coffee that went through the filter without percolating through the grounds bed - and it will carry fines with it.

Posted June 2, 2012 link

I tried this with moka coffee produced with a medium grind. I poured 150g of cooled coffee into a #2 Melitta and it quickly clogged. It took over 3 hours to drain and the filtered coffee was still opaque.

If you use the spent grounds as a filter how could you be certain that only undissolved solids were filtered out?
back to top
 View Profile Link to this post
jpender
Senior Member
jpender
Joined: 11 Jul 2011
Posts: 708
Location: California
Expertise: I like coffee

Grinder: OE LIDO
Vac Pot: S/S Moka Pot
Drip: Aeropress
Posted Tue Jun 5, 2012, 11:54am
Subject: Re: Coffee Extraction Discussion, Questions for the membership:
 

Netphilosopher Said:

Very intriguing.  This would imply A in the region of 0.2, but then it would only be based on "spent" coffee (minus extracted solids) so would have to be reduced (to be more representative) by extraction (1-E, actually).

Cp = Wb - (A*(1 - E)*C), where A=0.20 g/g [technically unitless].

Since extraction seems to range around 0.2, then a good estimate for A=0.16 (actually the (A*(1-E))) for immersion brews.

Posted June 5, 2012 link

Why? If this water is bound to the matrix the loss of soluble material might be irrelevant.

Doesn't "A" vary with brew method, grind, etc? That is to say, isn't it a measure of water retained, both bound and absorbed?
back to top
 View Profile Link to this post
showing page 10 of 14 first page | last page previous page | next page
view previous topic | view next topic | view all topics
Discussions > Coffee > Q and A > .  
New Topics updated topics   New Posts new posts   Unanswered Posts new unanswered     Search Discussion Board search   Discussion Board FAQ faq   Signup sign up  
Not Logged in: Log In to Postlog in
Discussions Quick Jump:
Symbols: New Posts= New Posts since your last visit      No New Posts= No New Posts since last visit     Go to most recent post= Newest post
Forum Rules:
No profanity, illegal acts or personal attacks will be tolerated in these discussion boards.
No commercial posting of any nature will be tolerated; only private sales by private individuals, in the "Buy and Sell" forum.
No SEO style postings will be tolerated. SEO related posts will result in immediate ban from CoffeeGeek.
No cross posting allowed - do not post your topic to more than one forum, nor repost a topic to the same forum.
Who Can Read The Forum? Anyone can read posts in these discussion boards.
Who Can Post New Topics? Any registered CoffeeGeek member can post new topics.
Who Can Post Replies? Any registered CoffeeGeek member can post replies.
Can Photos be posted? Anyone can post photos in their new topics or replies.
Who can change or delete posts? Any CoffeeGeek member can edit their own posts. Only moderators can delete posts.
Probationary Period: If you are a new signup for CoffeeGeek, you cannot promote, endorse, criticise or otherwise post an unsolicited endorsement for any company, product or service in your first five postings.
Cafe Solutions
Commercial sales and service, nationwide installation, equipment leasing options.
www.seattlecoffeegear.com
Home | Opinions | Consumer Reviews | Guides & How Tos | CoffeeGeek Reviews | Resources | Forums | Contact Us
CoffeeGeek.com, CoffeeGeek, and Coffee Geek, along with all associated content & images are copyright ©2000-2014 by Mark Prince, all rights reserved, unless otherwise indicated. Content, code, and images may not be reused without permission. Usage of this website signifies agreement with our Terms and Conditions. (0.334011077881)
Privacy Policy | Copyright Info | Terms and Conditions | CoffeeGeek Advertisers | RSS | Find us on Google+