These instructions are for making 10X TBE buffer and diluting to 1X TBE.

10X TBE Electrophoresis Buffer
Tris Base  108 g
Boric Acid  55g
0.5M EDTA 20 mL
Water to 1.0 L

First, dissolve everything in slightly less than 1 liter of water, and then adjust the volume to 1 liter by adding water.  There is no need to sterilize the solution.  If you notice that white clumps begin to precipitate in the solution, place the bottle in hot water until the clumps dissolve (technically described as the declumping procedure).  The solution can be stored at room temperature.  Some people report that autoclaving and storing in a refrigerator prevents precipitation.  To use as a buffer, dilute the 10X stock 10-fold.  Commercially available concentrated TBE may be 5X or 20X.  Dilute accordingly for 1X stock.

1X TBE Electrophoresis Buffer

10X TBE  100 mL
water         900 mL