Im fairly sure tooheys use a pale malt and a single dark malt that are specialy malted for them to a spec that we cant buy to make Old.
I love tooheys old and have had a few cracks at it.
I always end up making it a bit fuller and maltier than the Old at the club or pub. Probably because i use ale malt and brew with an ale yeast.
I would recomend using 50/50 ale/pils malts if youe using a light ale malt like IMC but 75% pils if your using MO for example........... you want that crispness that pils malt gives to a beer.
NExt you need to find a compromise between crystal and chocolate malts to give you a similar efect to the malt they use. I dont know the spec but perhaps ross could help you out with some info................ i think he may have "found" some that fell off a truck once........... years back!
The tooheys old i love at teh club had a sweetness, and a chocolate character and im still trying to get it right.
makt the beer to between 35 and 38 EBC, 10.44 to 1.046 and brew it with S-189 at 12 deg for a more authentic mouth feel and character.
try using pale chocolate at 550 EBC and crystal malt............... say 50% more than the anount of chocolate used to ballance it. adjust the amounts till you get the right colour.
Bitter with anything you want really but POR or cluster will get you closest. I like a bit at the finish but for an authentic version, just bitter it and no more hops!.
Thats about the best i can help you with. I could post 15 different recipes or ways to come to the same result but if you follow that you will get close.
Brew it, taste it and go...........mmmmmmmm needs more chocolate, or its to heavy, use all Pils next time.
Its you that has to drink it so make it to suit your taste.
The best thing about AG breing is if your trying to clone something, you ofter make it better!
Just filtered my german pilsner to a keg and i dont thing i will ever be able to stomach a Becks again
cheers