Not sure if it will help an infection that's already taken hold, but for our 45 - 65 pound dogs, we usually would give them a tablespoon in each of their two daily meals. We've since moved to a probiotic in both meals and 1 TBSP of yogurt in the morning meal just because after a hard winter of antibiotics, we found we needed something a little stronger than just the yogurt.
Meanwhile, about the infection. If you have any ear cleaner (Epiotic, OtiFoam, Nolvasen, etc.) clean the ear twice daily with that. A drying cleanser is the best because you don't want to leave the ear wet if you're fighting yeast. I think I remember reading a post on the board saying that they use red cider vinegar to clean their dog's ears...but my connection is too slow to be able to do a search
You can try it though by using the Search function up in the blue menu line
If it doesn't clear up in a few days, best to have it checked by a vet and get some meds. Infections can become chronic and actually result in permanent damage.