Mashing and boiling

[monkeyhands]

When I brew I leave a sterile spoon in with the mash and regularly stirr it for the whole mash time (my mash tun has a heating element which is controlled by a thermostat to keep the mash at the right temp and when it powers on I stirr the mash to prevent it burning on the element). Will this stirring harm the mash, alter the chemistry thats going on or reduce my efficiency etc. Secondly the kits I use state a 60 minute boil time but most recipes I see on here give a 90 minute boil time, what does the extra 30 minutes do for the wort

 

[ColoHox]

Firstly, there is nothing sterile about your mash. You don't have to worry about preboil sanitation.

The stirring won't affect your mash, besides causing it to lose heat.

A 60 min boil is standard for most beers. You will want to increase it to 90 min when using pilsner malt to boil off an off-flavor compound. When creating your recipe (do you use a particular software at all?), you will adjust your wort volumes to coordinate with the boil time. A longer boil can result in slightly darker beer, in addition to other factors such as hop utilization.