My next brew is going to test the effects of dry yeast rehydration on lag times, fermentation completion time, and overall attenuation.

I'm going to do 2 gallons of 1.050 or so wort split 4 ways. Pitch rates will be .5 grams dry weight per 2-qt sample, exactly half the normal pitch rate of 10-11 grams per 5 gallons. Expected results (hypothesis) in parenthesis.

**1. O2 devoid, Rehydrated (high starting cell count, anaerobic conditions, expect shortest lag, low/moderate attenuation)**

2. O2 devoid, Dry Pitch (low starting cell count, anarobic conditions, 2nd shortest lag, lowest attenuation)

3. O2 injected, Rehydrated (high starting cell count, aerobic conditions, 3rd shortest lag, most attenuative)

4. O2 injected, Dry pitch. (low starting cell count, aerobic conditions, expect longest lag time, moderate attenuation)

2. O2 devoid, Dry Pitch (low starting cell count, anarobic conditions, 2nd shortest lag, lowest attenuation)

3. O2 injected, Rehydrated (high starting cell count, aerobic conditions, 3rd shortest lag, most attenuative)

4. O2 injected, Dry pitch. (low starting cell count, aerobic conditions, expect longest lag time, moderate attenuation)

I'm choosing a pitching rate that is less than usual to exagerate the results. Let me know if you think it would be better to stick to actual pitching rates of 1 gram per .5 gallons.

Just to summarize, the order in which expect visible fermentation to begin is 1,2,3, 4 but the attenutation order from most to least is 3,4,1,2 based on the overall cell count that will be acheived given the conditions.

I hope this generates some good discussion and hopefully also clears up any misinformation that might be circulating. Hold on to your hats.