Monday the 27th of October
The following day I opened the fermenter and sampled for gravity and pH.
pH: 3.84
SG: 1.110
Temp: NA
Bugger, I forgot to measure temperature (?). Never the less it is interesting to see that pH had fallen from 4.7 to 3.8 due to the CO2 produced by the yeast. This is still in the start-up of the fermentation so yeast count is probably increasing. The resulting SG shows a decrease in gravity of 0.010.
Then I added the second nutrient pack:
Fermaid K: 2.0 g
MAP: 4.0 g
MAC: 3.0 g
K2CO3: 2.0g
Total: 64 ppm N and 57 ppm K+
I poured about 30 ml of must into the tube containing the nutrients, swirled it a bit to make a slurry and poured the content into the fermenter. To my surprise the must started to foam very aggressively, and I started to worry that I would be cleaning the floor for sticky honey. Fortunately, the foam stopped a bit before the edge. Then I stirred the must quickly to dissolve the nutrients, closed the fermenter and re-attached the airlock.
Evening Tuesday the 28th of October
pH: 3.64
SG: 1.088
Temp: 25.7 C (?)
So pH had droåped even further. Even though I add carbonate with both MAC and K2CO3 it might push pH a bit but it will fall again at least within one day. SG was surprisingly low. Gravity had fallen 0.022 in just one day - that is about 1/5 of the sugar available for fermentation, i.e. at this rate the fermentation could be over in just 5 days, WOW. Temperature was high, but I am not sure I trust the reading. The room was 23 C so the fermentation should have raised the temperature by almost 3 C - seems like a lot.
I then added the 3rd nutrient pack which was identical to the second one above. This time I did an effort to slowly dissolve some of the additives, pour it in, add more must to tube, dissolved a bit and pour it in, etc.
Never the less I still got a lot of foam.
Evening Wednesday the 29th of October
pH 3.63
SG 1.066
Temp: 24.1 C
It seams like pH has leveled out despite addition of carbonate so the must is probably now well buffered by bicarbonate. Once again SG had dropped 0.022 which I am still surprised about. Temperature is now within the expected range just a bit above room temperature - great
The 4th nutrient pack was added with was also identical to the second. Even though I planned for 5 nutrient packs I will not be adding the 5th. Since OG was 1.120 and I expect a FG to be 1.013 for an ABV of 15 % or a drop of 0.107 then an SG of 1.066 corresponds to 50% of the fermentation progress. Most articles says that you should not add nutrients past this point, so I will stop here and see what happens.
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The 5th nutrient was a bit smaller than the previous packs
Ferment K: 1.0g
MAP: 4.0 g
MAC: 3.0 g
K2CO3: 2.0 g
Total: 57 ppm N and 57 ppm K+
My plan was to add 300 ppm N and 255 ppm K+. As it turned out I will have added only about 240 ppm N and 200 ppm K+.
In the coming days i will continue to monitor SG and pH. If the rate continues the fermentation should finished by Saturday - that would be a new record for me :o). And I will use this SNA scheme with 4 additions in the future.
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