I am making a beer from someone else's recipe but I'm stuck using Wyeast 1968 London ESB and the recipe called for WLP013 London Ale. From what I'm seeing about these yeasts the WLP013 has a higher attenuation leaving the beer a bit drier than the 1968. Can I make this adjustment via the mash temp? I haven't seen a calculation that would tell you how many points of attenuation you'd get for a certain number of degrees lower mash temp.