Slower fermentation with dextrose ?

[greggn]

I've been running sugar washes quite successfully for the last few months. After inverting 9 lbs of table sugar I've had my washes run dry in five (5) days. So, I thought, why not try some dextrose ... what extra I spend on the sugar I save on not having to invert for 30 minutes per batch.

So, with everything else the same I ran a new batch with dextrose. Now, here I am eight (8) days later and the airlock is still bubbling. It's definitely not stalled, the yeast is active and working.

Is this normal ? I would have expected that the dextrose would be consumed faster than invert sugar.