Cold Beer

I have to admit up front, this is one of my favorite subjects…beer! More specifically cold beer. Recently I toured the Ellis Island Casino and Brewery in Las Vegas. Our guide stated how their customers wanted “cold” beer. Like most of you I immediately thought of Six Sigma Critical to Quality (CTQ) trees. Yes, it can be a curse.

As Lean Six Sigma practitioners we often hear words like “better, faster, cheaper” without anyone really understanding what that looks like. One of our duties is to convert abstract “voice of the customer” (VOC) requirements into a measurable output variable.

A CTQ tree is a six sigma tool used to transform VOC (cold) into something measurable (temperature). The same can be accomplished with words like affordable, colorful, clean, long and so on. So what temperature is “Cold” for beer? Answer: about 47 degrees (range for Ale beer is 44-52 degrees). So with random samples and a simple thermostat we can determine the amount of output variation and if our process is producing defects.

The process: after brewing is complete the beer is stored at desired temperature in an insulated storage vat. At some future point (no more than two weeks at Ellis Island Brewery) beer is transferred to casino bar via pipes that run across the roof (a very hot roof). The beer must remain at 47 degrees during the transfer process, a pipe coolant system is used for this purpose. Bartender then pours beer into cold glass and hands it to me (yes, I went to the Gemba multiple times during my research).

CTQ Tree

Customer Need	Drivers	CTQ Characteristics
Cold Beer	Storage Vat insulation	Beer stored at 47 degrees
	Transfer pipe coolant system	Beer transferred from storage to tap at 47 degrees
	Bar refrigerator/freezer	Beer mug at 38 degrees

By knowing the drivers that produce the VOC requirements helps us understand the systems that add value, shows us what we actually have control over (coolant systems and insulation), identify potential failures of those systems, and gives us a good starting point if we need to accomplish a root cause analysis. Bottom line: it’s very useful.

So the next time you hear abstract VOC requirements, think of cold beer and CTQ trees, I know I will. Hope you have a “great” day.