Possible reasons for non-fermenting cider must
On Monday I started my first attempt at cider making, and pressed around 18L of juice from the apples on a tree in our garden. All seemed to go well, until the yeast didn't start fermenting. And... 2 pitches later, its still not got going!
I'm trying to work out why this is. My first assumption was that I added too much SO2, but I'm now wondering whether the problem is elsewhere. Any thoughts would be much appreciated!
The most likely reason the must isn't fermenting is that I added too much SO2.
I didn't know the pH precisely on brew day, as I only had higher range strips that showed the pH was somewhere below 3.8. Based on this, I added campden tablets at the rate recommended for musts in the range 3.7-3.8, which was 3 per gallon (150ppm). I've subsequently got some strips in the right range, which have shown me that the must is actually pH 3.4. Therefore, I've added around 50ppm (1 extra tablet per gallon) more SO2 than I should have.
My first assumption was that this high rate of SO2 had killed the first two batches of yeast I'd pitched (5g of D47 @ 24 hours and then 5g of 71B @ 72 hours, both rehydrated as per instructions). Based on this, I gave the fermenter a really good rock and shake with the top off to try and release some of the remaining sulphites. Yesterday I got some free sulphite test strips. Although these probably aren't very accurate, they showed that my must had around 10ppm free sulphite left. I tried to reduce this a little bit further by adding 2ml of 3% hydrogen peroxide, which should have taken out around another 7ppm-ish.
After all of this, I made a third pitch of yeast (2 x 5g packs of 71B rehydrated) and assumed all should now get going nicely. However, nothing seems to have happened again. This makes me wonder, if something else at fault?
Other explanation 1: Too much yeast nutrient
I added 2 tsps of Wyeast yeast nutrient into the 18L of must. This is well over the recommended 1/2 tsp per 5 gallons on the pack, but less than the 1 tsp per gallon recommended in lots of places for less nutrient rich cider musts. Might there be a reason why overdosing with the Wyeast nutrient is killing the yeast?
Other explanation 2: New sanitizer killing yeast
My sanitation methods for this cider have been almost identical to the ones I've used for years with beer. The day before brew day, I soaked the fermenter in Chemipro Wash and then rinsed and filled with Chemsan overnight before draining and using. For the yeast rehydration, I rinsed out a measuring jug with Chemsan before adding boiled water and waiting for it to drop down to 35c. The only difference here between what I've done with many batches before is I'm using Chemsan for the first time, whereas I've only used Starsan before. I'd assumed these were pretty much identical, but is there a reason that this might be hurting the yeast -- especially in the rehydration? The yeast sank to the bottom of the jug and showed no signs of life when rehydrating each time, which is different from what I've previously seen with many beer yeasts (but not all).
Any ideas on what the issue might be would be appreciated!
Other info, in case its helpful:
- OG was 1.044 (and is still 1.044 a 6 days later)
- Must is sitting at 18c in temp controlled freezer
- I added 1st per gallon of pectic enzyme at the same time as SO2
- The juice tastes great, with no sign of burned matches etc. from SO2
On Monday I started my first attempt at cider making, and pressed around 18L of juice from the apples on a tree in our garden. All seemed to go well, until the yeast didn't start fermenting. And... 2 pitches later, its still not got going!
I'm trying to work out why this is. My first assumption was that I added too much SO2, but I'm now wondering whether the problem is elsewhere. Any thoughts would be much appreciated!
The most likely reason the must isn't fermenting is that I added too much SO2.
I didn't know the pH precisely on brew day, as I only had higher range strips that showed the pH was somewhere below 3.8. Based on this, I added campden tablets at the rate recommended for musts in the range 3.7-3.8, which was 3 per gallon (150ppm). I've subsequently got some strips in the right range, which have shown me that the must is actually pH 3.4. Therefore, I've added around 50ppm (1 extra tablet per gallon) more SO2 than I should have.
My first assumption was that this high rate of SO2 had killed the first two batches of yeast I'd pitched (5g of D47 @ 24 hours and then 5g of 71B @ 72 hours, both rehydrated as per instructions). Based on this, I gave the fermenter a really good rock and shake with the top off to try and release some of the remaining sulphites. Yesterday I got some free sulphite test strips. Although these probably aren't very accurate, they showed that my must had around 10ppm free sulphite left. I tried to reduce this a little bit further by adding 2ml of 3% hydrogen peroxide, which should have taken out around another 7ppm-ish.
After all of this, I made a third pitch of yeast (2 x 5g packs of 71B rehydrated) and assumed all should now get going nicely. However, nothing seems to have happened again. This makes me wonder, if something else at fault?
Other explanation 1: Too much yeast nutrient
I added 2 tsps of Wyeast yeast nutrient into the 18L of must. This is well over the recommended 1/2 tsp per 5 gallons on the pack, but less than the 1 tsp per gallon recommended in lots of places for less nutrient rich cider musts. Might there be a reason why overdosing with the Wyeast nutrient is killing the yeast?
Other explanation 2: New sanitizer killing yeast
My sanitation methods for this cider have been almost identical to the ones I've used for years with beer. The day before brew day, I soaked the fermenter in Chemipro Wash and then rinsed and filled with Chemsan overnight before draining and using. For the yeast rehydration, I rinsed out a measuring jug with Chemsan before adding boiled water and waiting for it to drop down to 35c. The only difference here between what I've done with many batches before is I'm using Chemsan for the first time, whereas I've only used Starsan before. I'd assumed these were pretty much identical, but is there a reason that this might be hurting the yeast -- especially in the rehydration? The yeast sank to the bottom of the jug and showed no signs of life when rehydrating each time, which is different from what I've previously seen with many beer yeasts (but not all).
Any ideas on what the issue might be would be appreciated!
Other info, in case its helpful:
- OG was 1.044 (and is still 1.044 a 6 days later)
- Must is sitting at 18c in temp controlled freezer
- I added 1st per gallon of pectic enzyme at the same time as SO2
- The juice tastes great, with no sign of burned matches etc. from SO2
