# Coffee Degas Equation

1. Mar 11, 2012

### fatpanda

Hi guys,
I've come across this article (http://www.probat.com/fileadmin/user_upload/Know-How/Entgasungsverhalten/2008_Vortrag_degassing_e.pdf [Broken]) about measuring the degas volume of fresh roasted ground coffee. They basically put ground coffee inside a gas tight bin and monitor the pressure and temperature to determine the degas volume. But, I can't figure out how they came up with this equation to determine the degas volume. Does anyone understand this equation? The original equation can be found in the article.

$$V_d[\frac{Nml}{500g}] = [\frac{(V_b-V_f)(P_u+P_i)}{P_n}\frac{T_n}{T_n+T_i}-(V_b-V_f)\frac{P_s}{P_n}\frac{T_n}{T_n+T_s}] \frac {500} {G_f}$$

Vd=degassing volume
Vb=bin volume
Vf=filling volume
Pu=surrounding pressure
Pi=pressure inside bin
Pn=norm pressure
Ps=inside pressure when measuring
Tn=norm temperature
Ti=temperature inside bin
Ts=temperature when measuring
Gf=filling weight

Last edited by a moderator: May 5, 2017