## Thursday, February 21, 2013

### Side by side starters Part 1 of 4

Recently I completed collection of data on a set of 42 side by side starters. Before I go into what this data means I figured I would present just the data and methods so that you can mull on this if you want.  The the experiment will be broken into four parts:
1. Daily data collected on month old yeast vs fresh yeast
2. Starting and final results of 40 fermentation with a range of inoculation rates and gravities
3. Analysis of the daily data
4. Analysis of the start and finish data.

### The Daily Data

Two15ml test tubes were prepared.  Both had a starting gravity of 9.42°P.  One was inoculated with 58 million cells taken from an active starter.  The second was inoculated with 60 million cells taken a slurry that had been in the refrigerator for one month.  Measurements were taken approximately daily and the date and time was recorded with each measurement.  These measurements included a refractometer measurement and a cell count with viability staining.  At the top of this post is a graph of the results.  The "active" description represents cells taken from the active starter, while the "inactive" represents cells taken from the refrigerator.  SBW is the sugar by weight.  This is the converted refractometer measurement using the equations derived in earlier posts.  The "eq" plots are a simple equation to show the relationship between consumed sugar and cells produced.  For the active culture this is 10 times the sugar consumed, and for the inactive it is 15 times the sugar consumed.

### Raw Data

 Day Active ABV Inactive ABV Active SBW Inactive SBW Active Live cells Inactive Live cells 0.02 9.42 9.42 59.8 51.2 0.88 2.279169 2.279169 4.71 4.71 141.9 152.7 1.17 3.038892 3.418754 3.14 2.355 1.22 170.17 163.9 1.66 3.342781 3.722643 2.512 1.727 1.83 3.190837 3.874587 2.826 1.413 177.1 178.2 2.12 3.494726 4.178477 2.198 0.785 2.17 3.494726 4.102504 2.198 0.942 152.9 199.1 2.63 3.418754 4.178477 2.355 0.785 3.21 3.266809 3.95056 2.669 1.256 145.86 3.22 4.558338 4.558338 168.3 172.7 4.08 4.558338 4.558338 176 215.6