Support/FAQ

Target alcohol content as there is high proportion of water in potatoes that limits the achieved alcohol so distillation will be more expensive on energy, also not a lot of nutrition in feedstock so may need specific nutrition package. When you make alcohol from potatoes, you get more methanol if compared to grains. Increased methanol is associated with pectins present in potatoes. It is not a major issue, just necessary to be careful during distillation, especially with heads cut.

For Cognac and Armagnac production, there are many grapes which can be used (see specific regulations) but all of them are usually poor in sugar: about 8 – 10 % ethanol content with a high acidity. Some of famous grapes: Ugni Blanc, Folle blanche.
They do not add any sugar and they ferment the must/juice only: the skins and the stems are removed during the pressing prior the fermentation.
The marc is not used in the production of Cognac and Armagnac.

In the industry both “blending at birth” and after aging blending are used. Distilleries where consistency is important have there own personal methods which are usually a combination of both. For instance some distilleries will age the heavier flavoured distillates for a few years as singles then add to base whisky for a further 3 or more years aging. Others age as singles, blend, then return to the barrels for a while to meld.

The yeast strains are selected according various substrates and conditions of fermentation.
For example:

• Production of Whisky and Bourbon: we have selected strains that work well on grain and at a wide range of temperatures, so we can use the same strain because the substrates are similar.
• Production of Whiskey and Rum (made from molasses): the sugar in the substrates are totally different (Rum: glucose, fructose and sucrose. Whiskey: glucose, maltose) so the strains have to be different.

After purchase, store the yeast in the distillery according the recommendations written on the technical data sheet.
Before adding the yeast to the fermenter, we recommend to rehydrate the yeast if you work in stressful conditions and want to achieve high ethanol content. The yeast is in dry format, meaning that there is no water in the membrane. The membrane is the most critical component of the yeast because it is where all the exchanges occur: sugars, vitamins, minerals etc. going in / ethanol and other metabolites going out. If the exchanges between interior and exterior of the cell do not work well, the yeast will not work properly and you can get sluggish or stuck fermentation.

There are multiple strains of yeast with various applications: baking, brewing, wine, spirit production – but also yeast used in the care of plants or for cosmetics.
Baking yeasts are yeast selected for breadmaking. The carbon dioxide produced by the yeast makes the dough rise which gives the bread its texture.
Brewing yeasts, as a distilling yeast, produce ethanol but the criteria of selection is different to meet the characteristics of each process.
Wine yeasts are selected to ferment glucose and fructose, and produces aromas – not to ferment maltose or maltotriose.
Finally, distilling yeasts use various types of sugar according the raw material the distiller uses, can reach very high ethanol content, ferment in stressful conditions, and develop aromas and flavors.

All of the products are proposed for specific applications (i.e. DistilaMax HT typically for neutral spirits made out of corn or wheat, DistilaMax MW for malted base whiskies).
Specific applications and conditions may require different yeast doses. You should contact your Technical Sales Representative to know more about the best recommended dose for your specific product. For example, a fermentation of malted grains woth no commercial enzymes or nutrients added will require a higher dose compared to other processes.

White rums are generally aged for some specified period of timeand then de-colorized, but there are some white rums that are not aged.

There are a number of factors which affect rum quality. These factors include:
– Sugar source (cane juice, cane syrup, or molasses)
– Type of yeast
– Fermentation and distillation methods and practices
– The aging and maturation process
– Quality of water used in spirit dilution.

To start we recommend maximum dosage and after achieving good results, optimize the dosage by gradual reduction.

When a brick/bag is open, it is recommended to store it in the fridge and use the yeast in the next 3 days.

It depends on the fruit. If it is Grapes, we will remove the skin and the stem during the pressing. With fruits like Apricot or Plum, we will remove the stone only. With Apple, we will press the fruit and ferment the juice.

SSF: Simultaneous Saccharification and Fermentation means that the addition of gluco-amylase is done in the fermenter.
In Sugar based fermentations a similar effect is achieved using Fed batches, objective is to lower osmotic stress.

Several parameters will influence your fermentation times:

• Temperature: cooler temperatures will typically be longer fermentations,
• Substrate / feedstock,
• pH:  3.6 – 5.3
• Agitation during fermentation: a moderate agitation will help,
• Choice of yeast: contact your local LBDS technical representative to receive advice on which DistilaMax strain is best for you according to the parameters and the distilled spirits you would like to produce,
• Adequate nutrition: this is a key factor to get healthy yeast and to get it working well and complete fermentation properly.

This does require some work and equipment. One method is to distill and take a density reading, such as with laboratory glassware designed to provide the amount of distillate needed and then to add the exact amount of fermented mash.
Add the same amount of water rinsing out first container.
Distill off the initial volume exactly and measure the density of this sample. Be sure temperature is correct.
Another instrument which simplifies the process and can give good results is to use an ebulliometer.

The ideal temperature depends on what you would like to get out of the fermentation. High temperature results in fast fermentation kinetics but can cause the yeast stress and therefore affect the flavour profile (high fusel oils production). Low temperature results in slow fermentation kinetics and impacts flavour (presence of volatile compounds). Temperature should also depend on the robustness of the yeast being used.
Many rum fermentations are carried out between 32°C – 33°C.

Some recommendations :
– use a yeast strain that is thermo-resistant
– use a yeast strain that has been adapted to the substrate you are using
– decrease initial density (gravity) of the medium you are fermenting
– use complex nutrients that is tailored for the substrate: some microelements (such as manganese) increases yeast’s resistance to stress factors including temperature.

Yeast strains have ideal fermentation conditions , for instance regarding Temperature we have done extensive sensory work on our strains and we know that some strains will give different aromatic profiles at  28°C or 33°C (82.4 F and 91.4 F).
Regarding distillation, when yeast strains are changed for various products , distillation cut points may need to be adjusted where going earlier into the heads cut or possily later into tails cut.

As fermentation is a living reaction, many conditions can impact this process. We can consider fermentation temperatures, pH, solids / sugar content that will impact the ability of the yeast to work.
Nutrition is another key factor, we need a balance of nitrogen, minerals, vitamins for the yeast to do its job.

The fermentation is an exothermic reaction so it is normal to have a production of heat which will be proportionnal of the ethanol content.

The fermentation is divided in various phases : a) lag phase : the yeast is getting ready to make the fermentation; b) log phase : it is the active phase of the fermentation during which the budding is very high ; during this phase, the yeast produces up to 33 times more ethanol than during the other phases ; c) stationnary phase: the yeast is less active ; d) death phase : the yeast dies and releases its content into the mash.

The primary nutrient we need to have is a suitable source of nitrogen where a blend of organic and inorganic sources is best. Inorganic nitrogen alone like DAP may help us but the yeast has many other requirements : minerals, vitamins, amino acids,  to consider for its various activities. A complex nutrient is ideal and if you are utilizing grain, you may wish to use a specific protease.

The amount of nutrients added is based on your substrate choice ( molasses or raw sugar vs grains) and the volume of substrates you are using to ensure the yeast can consume all the sugars preset in your mash.
You may want to perform available nitrogen analysis and dose nutrients according to this data but typically all substrates are deficient in either nitrogen or essential yeast vitamins and minerals.

During fermentation, yeast need nitrogen, minerals and vitamins in order to function properly. The YAN (Yeast Assimilable Nitrogen) should be around 250 – 300 ppm. Often it is necessary to add some nutrients to ensure a proper end to the fermentation. More detailed information is available on the TDS “DistilaVite“.

It depends on the fruit. If it is Grapes, we will remove the skin and the stem during the pressing. With fruits like Apricot or Plum, we will remove the stone only. With Apple, we will press the fruit and ferment the juice.

In the process of producing dry yeast, water which was in the cell membrane is removed. Rehydration allows water molecules to return and wakes up the yeast allowing for more efficient and consistent fermentation.

Yes it is better because with the rehydration you will preserve the qualities of the yeast. Rehydration is quite simple but has to be done correctly. You will find our recommendations on the packaging or you can contact your local Technical Sales Manager for additional information.

It’s better to use hot water (55-60 C) to do it.

If the barrel has been left dry for a while, first thing is to check for leaks. If you rehydrate before fixing the leaks, water may go inside the casks, and if it stays there for a long time it can get infected and cause off-flavors.
Then, the procedure is simple:
Add some 10-15 liter of hot water and place a silicone bung.
Roll the barrel over to ensure that the water wets all the internal surface of the barrel.
Check for obvious leaks. If none, let it rest for some more minutes for the water to cool down. Then, try to remove the bung paying close attention. If a vacuum has formed the barrel is watertight.
If no vacuum has formed, then check the heads and staves’ joints for indications of leakage.
Adjust the hoops as needed to tighten the structure.
Proceed to rehydrate by wetting the external surface of the cask with fresh water so the staves swell and tighten completely.
When dumping the water, don’t forget to check for off odors.

There is no real value in returning those small pieces back into the cask. They will be most probably exhausted and will not yield any appreciable contribution in terms of flavour or carbon surface. They will keep coming out needing to be filtered from your liquid every time and giving you more work than benefits.

Spraying the barrel during maturation will encourage ethanol loss across the stave gradient.
Conversely, sealing with wax will reduce oxygen transfer across the gradient outside to inside. It would tend to reduce maturation rate.

Our recommendation would be to assess spirit quality on diluted samples at final strength after resting for a few days. Avoid normal tap water for dilution, to avoid local mineral impact and effect – use demin water. Some spirits producers have seen advantage in using softened water which contains higher sodium ion levels to stabilise (minimise decay) of both flavour and colour.

Increased isoamyl acetate is not a typical problem in vodka production, but there are few wats to work on its reduction:
As isoamyl acetate has relatively high volatility, it can be quite easily decreased by increasing the heads cut.
Try to change the yeast: some yeast strains produce more isoamyl acetate than others.

Because the characteristics of the yeast are different, the results will be different. You can also play with the conditions of fermentation, without stressing the yeast either: the same strain at 28°C and 33°C will give similar aromatic profiles but not exactly the same.
On another hand, the same strain on different feedstocks e.g molasses and fresh cane juice, will give different aromatic profiles.