Izumi, Ontario Spring Water Sake Company, is one of my favorite places to stop when I'm in Toronto. It's located in the Distillery District, which has some fun to browse retail locations. The Mill St. Brewery is close by too, but I like the atmosphere at Izumi better.
The brewery is small, but I'm glad they have it open to the public for sale of retail items as well as a bar where you can try some of the variety of sake they have to offer. On a previous visit, I tried their sake tasting fleet. I was able to choose which I wanted to try, and I was really impressed with the knowledge from the staff.
The last time I was here I attended one of their brewery tours. They are $15 and you get to taste a variety of sake as well. It was interesting to learn about how Izumi makes their sake and how it differs from other breweries. I was glad to learn that they brew their sake in a more traditional manner, whereas most sakes are produced quickly and cheaply (even in Japan!). The woman who gave the tour was very informative. The crowd who attended the tasting was mostly couples (I went right before New Years), but I met another woman who recently returned to Japan and was glad to talk to her.
I would definitely recommend trying some of Izumi's products aside from the sake too. Their soap (which you can try if you use their bathroom) doesn't dry your hands and smells great. I believe they use some of the leftover materials from their sake brewing in the soap. One of my favorite things to get here is their rice ice cream! It's non-dairy and comes in some really great flavors. I've tried them all and really enjoyed them!
Go here!