Can the freshness of butter affect taste of cooking? Recently I made paneer (cottage cheese) butter masala following the recipe here.

However the taste was a bit off with the smell of butter. The butter had 3 months expiry date and I used it within one month from the date of manufacture.

I have to admit that as I was away from home I did not have proper measuring devices so I approximated the quantity.

I have experienced the same smell when butter gets old by a few weeks. So my questions are:


How does the "oldness of cooking butter" alter the taste of the recipe?
How does the quantity of butter (especially more than that in the recipe) alter the taste of the recipe?
If there is a change, can you please explain the reason or point to a link where such reasons can be found?
What is the best time to use butter so as to avoid any taste change? Or how "fresh" should the butter be to avoid any taste change?


Thank you community so much!
Butter can/will turn rancid if not stored properly; using rancid butter will completely destroy a recipe as it will have a strong smell and taste; probably why people use ghee instead of butter; smell it before using it.
In that particular recipe, I would imagine using more butter will not change much in term of taste or texture; unless you really messed up measurements from 2tsps.
This would be somewhat impossible to explain, adding butter will add more fat and some additional unctuosity to a dish; in that case, I imagine not much change will happen since there is also a lot of water and the cashew paste in the recipe.
As in any recipe, using fresh ingredient is the key to making a recipe work; even fats like butter or oils.


To keep butter fresh as long as possible: 


Buy only what you need (if you cannot store it properly)
Keep it cold in the refrigerator. (and properly wrapped).
Freeze unused butter (cut it in smaller chunks before, so you can only take out small amount at a time).
Use a butter "bell" that will keep the butter in water (don't forget to change water regularly).