When making our seasonal beer we ended up getting a pre-boil gravity sample that was way higher than expected, so we added water to dilute the mash. A new sample was taken and the first one must have been polluted because now we ended up with a to low gravity.
This lead us to a three hour boil to get the sought after OG. What can we expect from the fermentation? Is there any risk that the sugars we got are un-fermentable?