Add 12.5 quarts at 175F to the mash tun and allow to cool to 166F.  Once the tun has preheated, add grains and stir until the mash temp of 153F is reached.  Rest for 1 hour.  After an hour, draw off 5 quarts of the homogenized mash and boil it.  Once it has reached a boil (or shortly after), add it back to the main mash and rest for an additional 20 minutes.

At the end of the mash, add an additional 2.5 gallons of water at 170F.  Wait 5 minutes and drain (first sparge).  Once complete, add 2.75 gallons of water at 170F.  Allow to rest for 5 minutes and drain (second sparge).

If the desired amount of sweet wort is recovered before the runoff is done, reserve the remaining sweet wort for future starters.  Freeze or can to preserve.