Prep of LB plates and LB media

LB media is the universal  growth media  in Molecular Biology. Although  LB  is often thought to  stand for  Luria Broth , in fact it was an abbreviation for lysogeny broth and LB should perhaps be more  correctly referred to as Luria Bertrani broth.  There are many variations,  but here  is our favorite  recipe:  

LB Agar plates
Dissolve  7.5 g of  Bacto Agar ( Difco ) and 12.5 g of   LB medium  ( MP Biochemicals)  in  water, Q to 500mL in a "Wheaton"  1 liter glass bottle.  Check that pH is 7, if not titrate with NaOH. Autoclave at 121 for 15 minutes and store at RT.  To pour plates, melt on hotplate and dispense.  If adding antibiotic , cool to 45 degrees centigrade, add the antibiotic and pour.

LB Media
Dissolve  12.5 g of   LB medium  ( MP Biochemicals)  in water, Q to 500mL in a "Wheaton"  1 liter glass bottle.  Check that pH is 7 , if not  titrate with NaOH.  Autoclave at 121 for 15 minutes and store at RT.