Side by Side Starters 2 of 4

The five by eight matrix of tubes was set up to compare the results of varying inoculation rate from 30 million cells per milliliter to 120 million cells per milliliter.  The wort gravity was varied from 3°P to 15°P (1.012 to 1.060) in addition yeast was used from a starter at high krausen for one half and yeast that had be refrigerated for the other half.

To achieve the cell counts each slurry was counted and then varying volumes were added to the culture tubes.  For the active yeast cells these ranged from 2 to 5 ml, and for the inactive culture they ranged from 1 to 4ml.  Adjustments to gravity measurements would be needed because there is inherently residual sugar and alcohol in the slurry.

The array of gravities were achieved by diluting a 31.4°P wort and adding 1 to 5 ml. The remaining volume was filled with water to ensure each tube had 10ml of total volume.

The tubes were allowed to ferment for two weeks and then refrigerated and allowed to settle for several days.  The height of the yeast cake in each tube was measured.  Six cell counts were done and these were correlated to the heights of the remainder of the tubes to produce the final cell counts.  A linear fit based on the number of ml of slurry was used to equate milliliters of slurry to number of cells.  For this fit, the r2 value for the active culture was 0.9936 and the r2 value for the inactive culture was 0.9850

Raw Data

	SO4A-2	SO4A-3	SO4A-4	SO4A-5	SO4I-1	SO4I-2	SO4I-3	SO4I-4
15	15.7	15.7	15.7	15.7	15.7	15.7	15.7	15.7	initial sugar
12	12.56	12.56	12.56	12.56	12.56	12.56	12.56	12.56
9	9.42	9.42	9.42	9.42	9.42	9.42	9.42	9.42
6	6.28	6.28	6.28	6.28	6.28	6.28	6.28	6.28
3	3.14	3.14	3.14	3.14	3.14	3.14	3.14	3.14
	SO4A-2	SO4A-3	SO4A-4	SO4A-5	SO4I-1	SO4I-2	SO4I-3	SO4I-4
15	290	435	580	725	301	602	903	1204	initial live cells
12	290	435	580	725	301	602	903	1204
9	290	435	580	725	301	602	903	1204
6	290	435	580	725	301	602	903	1204
3	290	435	580	725	301	602	903	1204
	SO4A-2	SO4A-3	SO4A-4	SO4A-5	SO4I-1	SO4I-2	SO4I-3	SO4I-4
15	1281.536	1452.355	1824.593	2017.494	2238.316	2160.33	2682.706	2815.268	final cells
12	1200.739	1410.113	1403.444	1531.542	1678.082	1840.565	2072.807	2175.87
9	1030.552	1281.536	1275.025	1229.68	1316.986	1335.536	1707.368	2006.495
6	792.2474	926.4368	1021.271	1249.065	1275.435	1340.181	1629.525	1960.899
3	574.9571	751.3386	815.8027	1140.183	899.9871	1044.822	1261.642	1504.758