Fermentation will not start

[conorm]

I made a basic brown ale on Tuesday. Nothing unusual, OG1051, 19l batch, into fermenter at 22c. Admittedly, I used an out of date pack of BRY-97, sprinkled straight in as I always do. 18hours later no activity. So I pitched a pack of S-04 (also out of date but only by a year). That was a good 18hours ago as well, and nothing yet through the airlock. I usually see activity after 12hours, and full fermentation within 24h. A few small circular colonies floating on the top but no smell of CO2. I fear these are bacterial / wild yeast colonies from lifting the lid a few times.

I'm going to pick up a brand new pack of S-04 this morning. Can I save the wort by firing in some Camden tablets? Or am I better off re-boiling the lot?

Cheers

 

[Caramel Ox]

Pull a sample and check gravity and ph if you can. Airlock bubbles aren’t the same as fermentation necessarily.

 

[conorm]

gravity 1050
pH 5.5

still no signs of fermentation.

The wort has bay leaf in it (basically my all grain version of Andy Hamilton's bay and rosemary ale) which I've used before and never had an issue with fermentation.