Expert: John Snyder - 4/15/2008

Question
All grain brewing for 15 years.  Moved and water here is very hard (8.5ph). Used acid-blend to reduce ph for all previous batches. All previous batches finish at 1.020! Used multiple hydrometers to verify.
TO FIX THIS PROBLEM...
For new batches, no acid blend, Used bottled spring water(...thats what it said on the bottles) with 7.0 ph instead of my tap water . Multi-step mash (Add Alpha-amalyse to mash, 122 for 30, 150 for 30, 158 for 30, 168 for 10). Brewed 2 five gallon batches (all grain) Batch 1 OG 1.054, Batch 2 OG 1.048. OG perfect for both batches as per recipe. Cooled to 70. Pitched fresh White Labs Pitchable yeast (Belgian Blend & American Wheat) with expiration date on both of June 2008 and airated.  Added Yeast Nutrient to fermenter (never used this stuff before because I didn't have to).  Everything went perfect...   After 36 hrs, NO FERMENTATION!!!!  Not sure how to save these batches.
All I changed was the water (spring water, not tap) and used yeast nutrient.
Please help!!!
Thanks,
Jim

Answer
What was your mash Ph?How was the malt modification?
What temp did you hold your wort ,after pitching at 70.the temp of the wort should not be allowed to drop below the initial temp at pitching,for at least 24 to 36 hrs.as the yeast most likely drop out of suspension.I would repitch your yeast,and re-aerate,as you do so,if you suspect it was a temp change problem,and the fermenter is  less than 5 days.