I have had slow fermentations in the past but recently began to pitch a large amount of yeast (some say overpitch).
I found the batches with more yeast started faster, finished faster, and finished lower (higher AA %) than those pitched at a lower rate which started sluggishly, plodded along, and finished high (low AA %). My lagers are finishing in 5 - 6 days now though I do ferment at 60*F.
Even though you pitched two packs, without the starter to increase cell count you probably didn’t pitch enough yeast. The evidence is the sluggish behavior.
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