Fermaid K and other nutrient

[mux11]

I have been seeing more brewers throwing in a bit of nutrient in the wort at the end of the boil.. Would this be a recommended practice if I had been getting some off flavors?
Recently did a batch of the cream of three and used fermaid k for the first time.. Flavor is very different than past batches. I feel that im getting more malt and corn flavors but still get some red and green Apple.
Fermenting in glass at basement temp 64F consistant.. S05 at 1 envelope per 5gal fermentor.
Thoughts

 

[Bobby_M]

Relatively low gravity wort and dry yeast doesn't really require nutrient. Apple flavors is likely acetaldehyde. This can be avoided by ensuring that the fermentation temperature becomes slightly elevated when fermentation starts slowing down. 68-70F would be fine. The other possibility is oxidation. A beer that doesn't have acetaldehyde problems at the end of fermentation can develop it by getting exposed to oxygen too much. Every bit hurts.