I've had a go at cutting the top off a keg to make a kettle - see photo attached - with the aim being to try out an all grain 'brew in a bag'. I cut a hole about 30cm diameter to fit an old glass fry pan lid I found as I figured a lid would be needed to help keep a good constant mash temp and keep stuff from falling in. Anyways, will the rim left from the original keg make it difficult to remove the full grain bag after mash? Any advice? Perhaps I need to cut a bigger hole in keg and have a larger lid? Ta