Formula for correct pouring of beer (canned) according to this thread.
y = Angle of glass
x = Angle of can
t = Temperate of beer
vp = Pouring Velocity
gt = Glass temperature
gc = Glass cleanliness (inside fluidity(glass) surface resistance, a PhD subject on it’s own)
rt = Room temperature (ambient)
o = Height of beer foam of “head”
It must be stated that this is only a “rule of thumb” equation, as beer type and alcohol content (especially suspended sugars), distance from beer ejection from can to glass surface (here considered to be a constant so ignored), effects of static electricity (nylon carpets etc) on all the above variables, effect of users hand raising temperature of glass and reduction (as beer poured), atmospheric pressure, standing waves caused by the playing of music (ever noticed how beer served in the vicinity of Led Zeppelin concert is always flat?), etc etc.
Right then lets define suggested optimums, EP recons that 45% is correct for the positioning of the glass (in relation to the stream of beer sometimes rotating) this would indicate that if using a can the relationship between the static glass and (now) moving beer-can angle (as he is pouring from a static pump which is not a variable) can be expressed to mean that as the glass fills up the (actual) angle between the beer in the glass and the can will change (because you are having to move the can to maintain the 45% relationship). This will result in a modification to our formula to include an angular velocity (which to keep it simple will be in direct relation to pouring velocity (vp)) so as not to introduce another variable. This means that as the can empties the flow rate must remain constant (this will actually produce an acceleration in the beer can angle as it empties). We are going to define this variable as “p” and by it’s nature it will also be a constant (logarithmic? can’t remember). Anyway we have also omitted the rotation of the earth and the moons position (these will have an effect but so small we can ignore then here).
Also remember that we are pouring the beer onto the glass and not into the beer inside the glass that is whilst the “head” produced is largish. This will result in the glass temperate decreasing in relation to the difference between the beer temperature and the glass temperature (normally) as it’s poured (this is actually a horrific equation on it’s own). If no head is produced then we must pour the beer directly into the beer already into the glass in order to produce at least some head so this variable can be positive or negative depending on the concept of the observer. So we have the optimum delivery of beer meaning that a head must be produced (say “1”), this we will define as the optimum or constant “o” as previously indicated. Unfortunately when the beer slips down the side of the glass and hits the beer already in the glass (foam) is produced. This is the equation we are going to produce, and what’s important and what’s not. Proof is all that counts.
Is it this simple? Afraid not, it's a decade more complex.
:happy:
