For almost two days there have been no signs of fermentation other than some minuscule bubbles rising from the yeast and protein which had settled in the Fermzilla’s jar. These came to rest on the surface, making a tiny ring about six inches in diameter and later tracing the outline of the Tilt Pro, evidence of just how little fermentation turbulence there was. Today things have kicked up a gear, and I’m seeing not only the start of a slope in the fermentation graph, but also a building island of foam in the centre of the FV. The spunding valve has also just started to get enough input for me to make a sensible adjustment.
A slow start was to be expected I suppose. Fermentation is always going to be slow at 13℃, which is close to the bottom end of S189’s recommended range of 9-22℃. If anything I’m more concerned about my yeast starter (and pitching temperature) of 23℃ – let’s hope there’s no nasty off-flavours as a result there. I’m fermenting at 10 PSI throughout which will hopefully curtail the esters from here on in, and although I’m not dry-hopping at all I’ll need to reduce pressure down to nothing near the end of my fermentation schedule so that I can chuck in some Polyclar which will hopefully prevent chill haze.
Closing this entry on a final note, I’m really chuffed with how close I’ve gotten to reaching my predicted numbers on this brew, even if I don’t know why.
Could it be that it’s a fairly light beer compared to other recent efforts? I’m not sure what that’s got to do with my lower-than-previous mash / boil / chiller loss, which, if anything, would be slightly higher than reference on account of the 30 minute hop-stand. Then again, a lighter beer is going to be closer to the test run I did using just water, but again I don’t see why losses should increase with gravity. Maybe I just need to get many more brews under my belt and look at numbers again, recalibrating my equipment profile by taking a broader average.