Is my brew fermenting?

[purewhitesnow]

Hi guys just after some advice...
On Sunday I brewed an AG BIAB SMaSH 10 litre batch, SG 1040
All seem fine then added the yeast to the wort at 20 degrees celsius. Checked that the best before date on the packet had not expired.
I re-hydrated the yeast (5 grams of Gervin ale yeast from Wilko) however in retrospect realised the water I re-hydrated it in was probably too warm so the yeast may have been shocked?
After 48 hours since pitching the yeast there has been no airlock activity whatsoever, I have checked the seal on the fermenter all seems fine but nothing. I then added another 5 g of yeast re-hydrated in much cooler pre-boiled water and waited another 24 hours, still nothing. I appreciate airlock activity is not always proof of fermentation, it just seems a bit odd.
I've taken the lid off, there is a white foam on top which I guess is normal, it doesn't smell "off" or like vinegar, nothing like that but would've expected some Krausen at least on the upper parts of the fermenter. Temperature has been consistent 20-22 celsius.
Any thoughts on what is happening here?
Should I just leave it a week and then take a reading?
Any thoughts/advice welcome.

 

[Obadiah Boondoggle]

Hi guys just after some advice...
On Sunday I brewed an AG BIAB SMaSH 10 litre batch, SG 1040
All seem fine then added the yeast to the wort at 20 degrees celsius. Checked that the best before date on the packet had not expired.
I re-hydrated the yeast (5 grams of Gervin ale yeast from Wilko) however in retrospect realised the water I re-hydrated it in was probably too warm so the yeast may have been shocked?
After 48 hours since pitching the yeast there has been no airlock activity whatsoever, I have checked the seal on the fermenter all seems fine but nothing. I then added another 5 g of yeast re-hydrated in much cooler pre-boiled water and waited another 24 hours, still nothing. I appreciate airlock activity is not always proof of fermentation, it just seems a bit odd.
I've taken the lid off, there is a white foam on top which I guess is normal, it doesn't smell "off" or like vinegar, nothing like that but would've expected some Krausen at least on the upper parts of the fermenter. Temperature has been consistent 20-22 celsius.
Any thoughts on what is happening here?
Should I just leave it a week and then take a reading?
Any thoughts/advice welcome.

As you say lack of airlock activity doesn't mean that it is not fermenting

Even the tiniest hole will let the CO2 out - I always seal my fv's and the hole where the airlock is with Vaseline and still I have two fvs where there is never any airlock activity even though the fermentation always goes ahead fine

The fact that there is a white foam suggests to me that it is fermenting

If you wanted to satisfy yourself, you could take a gravity reading now, but the more times you break the seal (and the CO2 layer on top of your beer) the more chance you have of introducing an infection - particularly at this time of year

 

[Agentgonzo]

Unless you have a totally rigid (glass) fermenter, you can press gently on the top of the lid. This will increase the pressure and if there are no leaks, you should see a bit of movement in the airlock. If the water level in the airlock doesn't move, you have a small leak. If the water level does move, hold it there for a minute. If it slowly goes back down again, you have a pinprick leak somewhere.

White foam (as stated above) implies it's fermenting and all will be fine. If you do open it up again, have a quick sniff of the top of the fermenter. If it's full of CO2 you'll notice (that "bubbles up the nose feeling") and is another indication it's fermenting fine.

I had this a few brews ago and it was just that I hadn't topped up the airlock enough and there was a fraction of a mm gap that let the CO2 out without bubbling through the water (starsan)

 

[purewhitesnow]

Thanks for your advice. I smeared vaseline around the airlock hole seal and the airlock itself and this seems to have sorted the problem....reassuringly it is bubbling away now!

many thanks