A few recent posts have indicated that some members of the Forum are planning to or have used Fermentis’ new yeast TF-6. If you have, some feedback would be good.
In a recent post, I mentioned that Fermentis claims that in their taste testing, TF-6 stopped (or stalled) at around 1.010 (about 25g/L of sugar or medium dry). This was in typical French and American style musts which were somewhat low in YAN (Yeast Assimilable Nitrogen 90-110 mg/L), and only fermented down further in an English style must with a higher YAN (127mg/L).
Maylar commented that stopping at such a high SG is quite unusual and I must say that I agree. My knowledge of fermentation chemistry is pretty basic, however a bit of research suggests that this could happen with low YAN must (possibly accompanied by hydrogen sulphide… yuk!). It seems that YAN in juice can be measured but not easily so it isn’t commonly published, but for a variety of reasons can range from 50mg/L to 200mg/L.
The article by Fermentis is attached. It led to me wondering if TF-6 could be the new “miracle yeast” for slightly sweet cider. I had visions of using TF-6 until it stalled, adding priming sugar and bottling, then after the priming sugar fermented... “hey presto” sweet sparkling cider with no effort. Unfortunately it seems that it might not be quite that easy, but it might work with a cider made from very ripe late season apples from unfertilised trees, since such juice would typically be low in YAN especially if no DAP is added. After all, adding nutrient like DAP is a remedy for dealing with stuck fermentations.
I wonder if anyone with a bit more fermentation chemistry knowledge than me, has any views or would I be wasting my time.
In a recent post, I mentioned that Fermentis claims that in their taste testing, TF-6 stopped (or stalled) at around 1.010 (about 25g/L of sugar or medium dry). This was in typical French and American style musts which were somewhat low in YAN (Yeast Assimilable Nitrogen 90-110 mg/L), and only fermented down further in an English style must with a higher YAN (127mg/L).
Maylar commented that stopping at such a high SG is quite unusual and I must say that I agree. My knowledge of fermentation chemistry is pretty basic, however a bit of research suggests that this could happen with low YAN must (possibly accompanied by hydrogen sulphide… yuk!). It seems that YAN in juice can be measured but not easily so it isn’t commonly published, but for a variety of reasons can range from 50mg/L to 200mg/L.
The article by Fermentis is attached. It led to me wondering if TF-6 could be the new “miracle yeast” for slightly sweet cider. I had visions of using TF-6 until it stalled, adding priming sugar and bottling, then after the priming sugar fermented... “hey presto” sweet sparkling cider with no effort. Unfortunately it seems that it might not be quite that easy, but it might work with a cider made from very ripe late season apples from unfertilised trees, since such juice would typically be low in YAN especially if no DAP is added. After all, adding nutrient like DAP is a remedy for dealing with stuck fermentations.
I wonder if anyone with a bit more fermentation chemistry knowledge than me, has any views or would I be wasting my time.
