Jigger Volume Experiment

  The conclusions I’ve come to are all in line with common sense, for the most part. Wider bowls are less precise, and each jigger has different starting points— by which I mean to say that some jiggers are marked incorrectly. The main conclusion to be drawn from all of this is that all jiggers I’ve come across do what they’re supposed to do. They measure booze and ensure some degree of consistency.

PRECISE jiggers = same drink each time

TRUE jiggers = right drink each time

ACCURATE jiggers = proper recipe drink each time

Ideally, we have all three of those qualities in one set of jiggers. 

Clutterbuck Rating: The average of the Accuracy, Precision, and Trueness scores for each Target-- rated out of 10 points. This is is a pretty good representation of the overall score I've given a jigger, so that you don't have to read millions of numbers just to get the point of this.

*Arranged in order of best to worst results*

Cocktail Kingdom Japanese Jiggers (1oz/2oz & .5oz/.75oz)

Clutterbuck Rating: 9.28/10

OXO Double Jigger (.75oz/1.5oz)

Clutterbuck Rating: 8.92/10

OXO Steel Angled Jigger (2oz)

Clutterbuck Rating: 8.88/10

Cocktail Kingdom Leopold Jigger (1oz/2oz)

Clutterbuck Rating: 8.37/10

 So here's the haps:

In this experiment, I've tested the accuracy, precision, and trueness of single pours and averaged multiple pours of common (and some uncommon) jiggers on a .01g scale. I've used them all before, so none of the error in my pours came from monkeying around trying to use the things. This will be an ongoing search, and the results will speak for themselves to some degree, but the point of the experiment is to determine two separate judgements. All measurements and math were done in grams, and the results were converted to ounces, in order to avoid any errors in calculation.

Questions:

1. How close to the volume claimed are the lines and tops of the jiggers? i.e. How close is the 1oz line to holding exactly 1oz?

2. How much does the volume of each pour vary between pours of the same volume? i.e. Will I pour exactly 1oz each time I try to pour 1oz?

3. Will the average of my efforts across many pours equal the target? i.e. Will the average of my efforts equal 1oz if I try to pour 1oz 12 times in a  row?

So here are some words and the process:

Target: These are the volumes that the jiggers' lines and tops purport to hold.

Precise Pour: After placing the jigger on a .01g accurate scale, I meticulously and carefully filled the jigger to each of its markings and to the tops of each side to determine their true volumes in ideal lighting and with no time constraint. I recorded each of these figures as the "Precise Pour". 

ACCURACY: The extent to which the Precise Pour agrees with the Target.

Pour 1-12: For each of the Target Pour volumes, I poured and recorded the volume 12 times. I poured as if I were making a drink, but into a quart container atop the gram scale. 

Pour Difference: The volume difference between the lowest and highest volume in Pour 1-12.

PRECISION: The extent to which Pour 1-12 agree with their mean.

Average Pour: The average of Pour 1-12 for each target.

TRUENESS: The extent to which the average of Pour 1-12 agree with the Target.