Posted Thu Mar 7, 2013, 9:14am Subject: Does a flow restrictor improve shot quality?
I am wondering if a flow restrictor improves shot quality or not? I am thinking of trying to add one to my Silvia just for fun. I think larger machines like the rocket have them as well as commercial one too. Do they play a big role during extraction?
ddubick Senior Member Joined: 1 May 2012 Posts: 76 Location: Calgary, Alberta, Canada Expertise: Just starting
Espresso: Nuova Simonelli Appia 1Gr Grinder: Macap M5, Nuova Simonelli... Roaster: Behmor 1600
Posted Thu Mar 7, 2013, 10:51am Subject: Re: Does a flow restrictor improve shot quality?
The machines that have flow restrictors are heat-exchanger (HX) machines. Your Silvia is a completely different breed of machine - single boiler dual use (SBDU).
As I understand it flow restrictors are used in HX machines to create a pressure ramp profile to achieve pre-infusion or dampening of the coffee grounds.
There are no extra chambers in a SBDU grouphead to fill by flow restriction to acheive pre-infusion.
Pre-infusion in SBDU is usually done (from my experience) by running the pump for a few seconds (not letting full pressure build up), turning it off for a few seconds, and then turning it back on to brew. This is what the pre-infusion function on my old Silvia's Auber PID did. Run for 2.5s, off for 2.5s, brew for 28s.
Flow restrictors are also used in an HX thermosyphon loop to control the temperatures, which is completely inapplicable to a SBDU.
Someone PLEASE correct me if I'm wrong on any of this.
D4F Senior Member Joined: 15 Mar 2012 Posts: 1,225 Location: USA Expertise: I like coffee
Espresso: Gaggia Classic PID Grinder: Preciso
Posted Thu Mar 7, 2013, 12:00pm Subject: Re: Does a flow restrictor improve shot quality?
Similar to above. I recently read about flow restrictors and gicleurs to try to understand the Oscar Mod thread. Helen or Markarian may chime in, but I looked here
Posted Thu Mar 7, 2013, 12:37pm Subject: Re: Does a flow restrictor improve shot quality?
Thanks. I was just wondering. A video of a bottomless pull on a rocket machine gave me the idea. I didn't know it had to do with pre infusion. I simply wanted to slow a pull for optimal extraction which I can do by bleeding some pressure with the steam valve.
Symbols: = New Posts since your last visit = No New Posts since last visit = 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 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.
= No New Posts since last visit 