Hi all. I am doing a port following GA's now famous receipt. I read about adding oak chips which sounds a good idea to me. Can someone recommend what type as I see various types on Homebrew sites. Sherry. French. Whiskey. Medium. Heavy. Any advice and suggestions appreciated. Also when should I put them in and for how long. So far about a week in and have just put through a jelly bag and into a demijohn with some extra sugar. Thanks in advance.