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Classic Lloyd

Sourcing bacterial strains for rum fermentations

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13 hours ago, Silk City Distillers said:

Probably one of the best recent PhD dissertations I've read recently on this exact topic:

 The microbial ecology of a rum production process

Dr. Victoria Green - Working at Bundaberg Rum in Australia.

Thanks for sharing this - it's fantastic. We're currently running a series of fermentations with a culture cultivated from fresh-pressed sugarcane, which have over a few generations, has whittled down to one dominant yeast, with 1-2 other yeast species also in there.  I'd assumed that the dominant species was S. cerevesiae, but this article makes me wonder if I'm not working with something different.

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On 1/24/2019 at 9:07 AM, Classic Lloyd said:

...I'd assumed that the dominant species was S. cerevesiae, but this article makes me wonder if I'm not working with something different.

Have you found out since? 

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60,000,000 litres / year output of 96-99% ABV Neutral Cane Spirit from the largest Molasses based Distillery in Australia - https://wilmarbioethanol.com/

2 x 1,000,000L (ML) Continuously run FV system - alternating back & forth and is the BioStil Process that is utilised in Brazil & India.

but what there's more..

100% S. Pombe culture - a ~30%Brix vinasse output results from the focus  to minimise the actual water intake/ demand for the operation of the system and the Pombe provides more 'optimal' stability over 5-6 day ferment in those volumes versus S.cerevesiae.

Yeast cake is consistently removed to manage and control yeast cell health & viability.

For any Aussie out there reading this - the Yeast Cake from this distillery was also the Vegemite yeast extract production site between 1951 to 1971 - aside from CUB in Melbourne.

 

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Yes - CUB is Carlton United Breweries - historically the largest Brewery group in Australia.

This Molasses Ethanol Distillery was next biggest yeast production site & apparently produced a superior yeast extract for the day - not S. Pombe.

Anyone used Aspergillus in a molasses/ rum wash to push Citric and Malic acid output rather than Lacto?

Just reading recently also that the sugarcane bagasse & more specifically the cane wax/ external cuticle layer is high in C16 & C18 fatty acids..

Within the end-to-end process sugarcane mill & distillery facility that I work in - I have noted the 'rum oils' many times as a distinct surface sheen/ slick when clarified juice is cooled allowing the oils to coalesce.

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There are plenty of other plant based sources of long-chain fatty acids and waxes that are fairly similar, depending on what your target is.

Depending on what you want to target, it's fairly easy to find a plant-based match.  You can even engineer a specific profile using GRAS ingredients.

For example, if I want to target C12-C16, I might use a refined coconut oil (no, you don't get any coconut flavor or aroma in the distillate).

If I want a high percentage of C16 - Rice Bran Oil.

If I want to target C18 - Almond Oil.

C16-C18 - Peanut Oil.

If I want a higher percentage of waxes - Beeswax, or heck, just go with cane waxes as well.

Folks who mash corn high in fatty acids see similar oil-slicks - corn oil high in C10 and C16.

Probably more interesting are the long-chain wax esters, meaning you'd probably need two components to match.  Like Peanut Oil and Beeswax.

Which one of these makes the delicious rum oil?  Which one of these tastes terrible?

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Y'all may enjoy this paper on "bauer oil" that turned up while translating Kervegant's 1946, Rhum and Canne Eau-de-vie.

Bauer oil may be a match for Arroyo's "rum oil" and these ideas go all the way back to Micko and then across to old authors that talked of Cognac oil. The "oil" is a complex mixture and has both saponifiable and non-saponifiable parts. The bulk of it is saponifiable. The portion that isn't may be the realm of rose ketones and all that nonsense.

In my experience with the birectifier, when concentrated, these fractions aren't harmonious and can seem intensely acrid, but when diluted to normal levels and part of a sensory matrix that includes ethyl acetate they define a spirit and represent quality.

One thing recently learned about Pombe fission yeasts is that they have on average much thicker cell walls than budding yeasts. This gives their lees a lot more potential for aroma when broken down. In a typical ferment, fission yeasts also have the tendency to produce more esters because the cell wall at the point of their division is extra thick and a portion dissolves into the ferment upon successful separation.

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15 hours ago, Simpo said:

Have you found out since? 

That strain was definitely a S. Cerevesiae. It eventually adapted to be a prolific producer of acetaldehyde and we ended up shelving it.  Generally speaking, our experience is that wild strains lose a lot of their dynamic nature (and diversity) in just a few generations.

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3 hours ago, Curators Reserve said:

Anyone used Aspergillus in a molasses/ rum wash to push Citric and Malic acid output rather than Lacto?

Is this a thing? I work occasionally with aspergillus and have found it to be very finicky on anything but grains. (I suppose you could add inoculated grains, but then it would cease being a rum)

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Commercial Citric acid production is typically Apergillus in a molasses wash ferment.

Malic Acid is also produced by Aspergillus..

Aside from inherent LAB in freshly crushed juice - ester formation from increased Citric & Malic acid output from Aspergillus is of interest..

 

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On 9/30/2019 at 6:26 AM, Classic Lloyd said:

Is this a thing? I work occasionally with aspergillus and have found it to be very finicky on anything but grains. (I suppose you could add inoculated grains, but then it would cease being a rum)

There is a style of shochu made with koji-rice and sugar (kokuto shocho), as well a sort of similar process for batavia Arrack made with molasses and an inoculated rice starter. 

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On 9/30/2019 at 9:15 AM, bostonapothecary said:

In my experience with the birectifier, when concentrated, these fractions aren't harmonious and can seem intensely acrid, but when diluted to normal levels and part of a sensory matrix that includes ethyl acetate they define a spirit and represent quality.

 

Not uncommon when talking about flavor and aroma compounds, where an increase in concentration can take a taste or smell from pleasant to awful, or worse.  That creates a whole other level of complexity where it simply isn't about creation of a specific compound as part of the process, but the creation of that compound at a specific concentration.

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