Extract Fruit Lambic

For my Blackberry Sour Blonde I added the oak later in the process and added a lot. For my Lambics I have added it at pitching. I would caution to add a small amount in primary and you can always add more when you rack onto the fruit in a year. It is difficult to get the oak out of the fermentor once it is in there if you are getting too much oakiness. I did that with my first Lambic, had to rack to my bottling bucket, dump the trub in another sanitized container, then get the oak out, then rack the trub and beer back into the carboy after cleaning and sanitizing it again. It was a major pain. As far as soaking oak first, I have not, but the oak I use is from a winery that they used in the SS aging tank for a red wine, so mine have some red wine character, but not enough to really stand out when I taste the beers.