Apr 9, 2009|
Question (Part 2)

From Roastmaster Tom

.... (in the last post, Roastmaster Tom asked about pre-infusion)

For the pulse brewing parameters, what specifically are we looking for? Should both the "wetting" stage and the "dry" stage be the same length of time? How long should that be? Should they differ in time and if so why? Does the roast level or caf/decaf affect those parameters? Does the size of the batch affect those parameters? As you can see I have a number of questions with what appears to be very little info available. Can you please help me understand how best to use these functions on your equipment?

Thank you.

Tom Walsh

Cambria Coffee Roasting Co.


(I addressed Tom's questions about pre-infusion in my last post. Now, for his questions on pulse brew...)

Pulse brew is a tool that allows the user to manage water delivery time. This tool is valuable for increasing the water contact time for smaller volume brews on multi-batch equipment.

Let's say you want to brew one-half gallon of coffee and you have a 4-minute water cycle for a one-gallon brew. The half-gallon would be dispensed in 2 minutes, with approximately half of the bed depth. The resulting brew would likely be weak and under extracted compared to the one-gallon brew.

Using pulse brew, you can increase the water contact time with the grounds. A pulse brew routine might consist of an initial ON time followed by a series of OFF and ON times. Similar to the pre-infusion setup, the initial ON time needs to be sufficient to saturate the grounds and get the bed in float. The Off time can be as little as 5 seconds, followed by ON times as little as 5 seconds. As an example: a pulse brew routine of 25 ON - 05 OFF - 5 ON would result in adding over 1 minute to the original 2 minute dispense time.

If you want to read more about the roles of pulse brewing and pre-infusion, check out this article from Tea and Coffee Asia written by yours truly.

Pulse Brew and Pre-Infusion -- New Tools for Filter Drip Brewing

Happy Brewing,
Dr. Brew


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