Conditions that affect how much malic acid Lalvin 71B can metabolise

[Steve Drew]

Dear folks,

I have started using 71B in the hopes of reducing titratable acidity in some of my 'end of season' ciders. For those that may be confused by that, I live in Tasmania in the southern hemisphere.

My first attempt with 71B was with a blend of Sturmer Pippin (34%) and Sundowner (66%). Additions to the juice were 2tsp pectinase and 2tsp of Bintani yeast nutrient. Fermentation to dry took around 4 weeks with temperatures between 10C and 14C. TA (malic) of the blend before fermentation was 10g/lt and it reduced to 6.5g/lt creating a mild but 'bright' acidity to my palate. The 35% reduction in TA was everything I hoped for.

More recently, I picked what I believe are ripe Red Sentinel crabapples, which make a pleasant flavoured, sweetish juice, though as you would expect quite sharp with a TA (malic) of 12 g/lt. I followed the same procedure as above, with the same additives to the juice at initiation of the fermentation. This time the temperatures were between 8C and 11C and the primary fermentation took nearly 6 weeks. I noted that the finishing SG for primary fermentation was around 1.007 which was more than normal. I also noted that the finishing TA was only marginally lower than the initial TA at around 11 g/lt. 

Being a bit sensitive to sulphites, I do not treat the juice. I rinse bottles in clean water after washing and before bottling. These processes were the same for both fermentations, above.

At the moment, I can only see perhaps a correlation between temperature and amount of malic acid metabolised. There are, undoubtedly, other factors and considerations that I am not aware of.

Can anyone share any insight into what affects the amount of malic acid that 71B can metabolise please?

Steve

[Claude Jolicoeur]

Steve,

I don't have a complete answer to your question, but there are a few points you might consider concerning this.

The 71B yeast strain is, according to the data sheet, sensitive to the killer factor. This means this is a strain that has more difficulty to become dominant if there are other yeast strains present that have the killer factor. Then if you want to make sure the 71B becomes the dominant yeast strain in your cider, you should eliminate the other native yeasts that are present in the must - and this is done either by sulfite addition or by pasteurisation of the must before yeast inoculation. So, maybe in your second batch, the 71B didn't succeed to become the dominant strain.

You say you are sensitive to sulfites. However, sulfite added before yeast inoculation will be entirely bound (or degraded) by the time the cider has finished fermentation. I am also quite sensitive to sulfite, but it is only sulfite added at bottling time for conservation that may be troublesome.

[Steve Drew]

Thanks Claude,

That is interesting about the (K2) killer factor sensitivity. I suppose if the must was particularly redolent with wild yeast with that killer factor, enough to kill and so outcompete 71B then that could be a factor indeed.

I would note that all equipment was sterilised before use, suggesting the juice as the likely source if that was the case. Just one or two slightly fermenting fruit, even in the washing bin might provide a viable source I imagine.

I note also that there were no ‘interesting’ flavours indicating that it may have been a cerevisiae strain rather than one of the other ‘funky’ tasting varieties perhaps.

It is interesting that even with nutrient added, that rather than stopping with a SG around 1.000 it stopped at 1.008 which might indicate a strain that had reached its alcohol tolerance, perhaps. That certainly would not be 71B.

So, without any further input I would follow your advice in terms of sulphiting the juice and trying again. Alas, next year. Sigh!

I understand that with judicious application of sulphite that SO2 becomes bound and part of the lees by the end of fermentation, but I have had such strong reactions, in terms of effects on breathing, from wines and ciders that have had ‘preserving’ levels of sulphite added at bottling or riddling that I have been overly cautious perhaps.

Thanks for your thoughts and help. I look forward to the next season of apples, cider and learning with anticipation.

Warm regards

Steve

 

 

Steve Drew PhD MHEd                            ORCiD: 0000-0002-8601-9815

Senior Lecturer - Professional Learning and Networks for Teachers

Tasmanian Institute of Learning and Teaching | Academic Division

University of Tasmania

Private Bag 133 Hobart TAS 7001

T +61 3 6226 2387 | M +61 416 158 367

utas.edu.au

 

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[luis.ga...@gmail.com]

I wonder if the higher TA of the second batch of cider, with presumably a lower pH, could have affected the effectiveness of the acidity reduction of the yeast. With such a high acidity, you are presumably out of the normal range of acidity of a cider/wine and the yeast has maybe not been proven effective for such must.

Louis

Le lundi 30 août 2021 à 19:22:49 UTC-4, steve...@utas.edu.au a écrit :

[Andrew Lea]

I would agree with all that Claude said.

In addition, it’s worth noting that Red Sentinel is not a variety of Malus domestica. . It’s an ornamental cultivar of Malus x robusta, which is hybrid of the Asian trees Malus baccata and Malus prunifolia and was bred by Notcutts Nursery in the 1950's. 

Many non-domestica apple species have different chemistry from that of domestica.  In particular their acid composition and the ratio of citric to malic acid may vary.  I have been unable to find exact data on M. robusta but I would suspect it may contain a high proportion of citric acid which (unlike malic) is not metabolised by 71B. The high residual SG could also be a consequence of higher levels of unfermentable sorbitol. 

Andrew

Wittenham Hill Cider Portal
www.cider.org.uk

On 31 Aug 2021, at 09:55, Steve Drew <steve...@utas.edu.au> wrote:



Thanks Claude,

That is interesting about the (K2) killer factor sensitivity. I suppose if the must was particularly redolent with wild yeast with that killer factor, enough to kill and so outcompete 71B then that could be a factor indeed.

I would note that all equipment was sterilised before use, suggesting the juice as the likely source if that was the case. Just one or two slightly fermenting fruit, even in the washing bin might provide a viable source I imagine.

I note also that there were no ‘interesting’ flavours indicating that it may have been a cerevisiae strain rather than one of the other ‘funky’ tasting varieties perhaps.

It is interesting that even with nutrient added, that rather than stopping with a SG around 1.000 it stopped at 1.008 which might indicate a strain that had reached its alcohol tolerance, perhaps. That certainly would not be 71B.

So, without any further input I would follow your advice in terms of sulphiting the juice and trying again. Alas, next year. Sigh!

I understand that with judicious application of sulphite that SO2 becomes bound and part of the lees by the end of fermentation, but I have had such strong reactions, in terms of effects on breathing, from wines and ciders that have had ‘preserving’ levels of sulphite added at bottling or riddling that I have been overly cautious perhaps.

Thanks for your thoughts and help. I look forward to the next season of apples, cider and learning with anticipation.

Warm regards

Steve

 

 

Steve Drew PhD MHEd                            ORCiD: 0000-0002-8601-9815

Senior Lecturer - Professional Learning and Networks for Teachers

Tasmanian Institute of Learning and Teaching | Academic Division

University of Tasmania

Private Bag 133 Hobart TAS 7001

T +61 3 6226 2387 | M +61 416 158 367

utas.edu.au

 

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From: cider-w...@googlegroups.com <cider-w...@googlegroups.com> On Behalf Of Claude Jolicoeur
Sent: Tuesday, 31 August 2021 10:48 AM
To: Cider Workshop <cider-w...@googlegroups.com>
Subject: [Cider Workshop] Re: Conditions that affect how much malic acid Lalvin 71B can metabolise

 

Steve,

I don't have a complete answer to your question, but there are a few points you might consider concerning this.

 

The 71B yeast strain is, according to the data sheet, sensitive to the killer factor. This means this is a strain that has more difficulty to become dominant if there are other yeast strains present that have the killer factor. Then if you want to make sure the 71B becomes the dominant yeast strain in your cider, you should eliminate the other native yeasts that are present in the must - and this is done either by sulfite addition or by pasteurisation of the must before yeast inoculation. So, maybe in your second batch, the 71B didn't succeed to become the dominant strain.

 

You say you are sensitive to sulfites. However, sulfite added before yeast inoculation will be entirely bound (or degraded) by the time the cider has finished fermentation. I am also quite sensitive to sulfite, but it is only sulfite added at bottling time for conservation that may be troublesome.

 

Le lundi 30 août 2021 à 19:22:49 UTC-4, steve...@utas.edu.au a écrit :

Dear folks,

I have started using 71B in the hopes of reducing titratable acidity in some of my 'end of season' ciders. For those that may be confused by that, I live in Tasmania in the southern hemisphere.

 

My first attempt with 71B was with a blend of Sturmer Pippin (34%) and Sundowner (66%). Additions to the juice were 2tsp pectinase and 2tsp of Bintani yeast nutrient. Fermentation to dry took around 4 weeks with temperatures between 10C and 14C. TA (malic) of the blend before fermentation was 10g/lt and it reduced to 6.5g/lt creating a mild but 'bright' acidity to my palate. The 35% reduction in TA was everything I hoped for.

 

More recently, I picked what I believe are ripe Red Sentinel crabapples, which make a pleasant flavoured, sweetish juice, though as you would expect quite sharp with a TA (malic) of 12 g/lt. I followed the same procedure as above, with the same additives to the juice at initiation of the fermentation. This time the temperatures were between 8C and 11C and the primary fermentation took nearly 6 weeks. I noted that the finishing SG for primary fermentation was around 1.007 which was more than normal. I also noted that the finishing TA was only marginally lower than the initial TA at around 11 g/lt. 

 

Being a bit sensitive to sulphites, I do not treat the juice. I rinse bottles in clean water after washing and before bottling. These processes were the same for both fermentations, above.

 

At the moment, I can only see perhaps a correlation between temperature and amount of malic acid metabolised. There are, undoubtedly, other factors and considerations that I am not aware of.

 

Can anyone share any insight into what affects the amount of malic acid that 71B can metabolise please?

Steve

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[Steve Drew]

Thank you Andrew,

That all sounds like further important pieces to the puzzle.

If sorbitol is present in the same sort of proportions to the pears that I used to make perry this year (Yellow Huffcap 46%, Beurre Bosc 50%, Gin 4%)  then a finishing SG closer 1.010 does make sense.

The knowledge shared by you and Claude has inspired some further experimentation. I will see if I can find any remaining crabs to conduct a small study. But, it will be a close thing this late in our season.

Otherwise, next year. 😊

Steve

 

 

Steve Drew PhD MHEd                            ORCiD: 0000-0002-8601-9815

Senior Lecturer - Professional Learning and Networks for Teachers

Tasmanian Institute of Learning and Teaching | Academic Division

University of Tasmania

Private Bag 133 Hobart TAS 7001

T +61 3 6226 2387 | M +61 416 158 367

utas.edu.au

 

To view this discussion on the web, visit https://groups.google.com/d/msgid/cider-workshop/24BEA9B6-82D5-4CC5-91FC-016CDD58F6B5%40cider.org.uk.