Molasses

To find large quantities of molasses, try farm stock feed dealers. They will sell black strap molasses for horse or cattle feed supplements. Different types of molasses have different sugar contents. (See http://www.syrupmakers.com/ for different kinds of molasses and the mills and plants / procedures that go into making them.) It therefore pays to measure the specific gravity (SG), until you get the desired concentration. Due to its high osmotic pressure, it needs to be diluted to less than 25 Brix (weight % sugar), or else the yeast wont be able to get started on it. Unfortunately, due to it sometimes only having around 46% sugar, this means you only get a sugar content of 14%, and a final alcohol of around only 6-7%. To get around this, you may need to feed the molasses to the wash in several stages.

In response to some questions about using molasses ..

I intend to produce fuel ethanol using molasses as a feedstock. This will provide the sugar source but I have been told that on its own it does not contain enough nutrients for optimum alchol conversion.

Somebody suggested that you can add corn steep liquor (CSL) - does anybody have experience of this and what ratio of molasses (at 49% sucrose) to CSL would you use? Or is there a better alternative.

David replied ..

This is simply not true most of the time. Molasses generally contains more than enough nutrients although where high temperatures have been used in its processing it can occasionaly be a little deficient in one or two vitamins (generally not a problem as yeast require very small amounts of these). The problem is not the nutrients but the presence of bacteria and wild yeasts which molasses contains a lot of. To get round this you need to introduce larger than normal amounts of yeast and to have your pH right so the good yeast quickly get the upper hand and quickly dominate. This then leads on to the proper fermentation temperature as too quick a fermentation raises the temperature and can quickly kill the yeast. If you look after both these aspects you should have very little problem.

One of the problems with molasses is that it often dosnt have the sugar content that the seller claims and it therefore will not produce as much alcohol. There is often a lot of unfermentable material as well. A standard 44 imperial gallon drum (US 55 gallons) contains something like 260 to 280 kg of molasses. This contains a lot of inert material. If buying and using molasses for this purpose one needs to constantly monitor and check the brix level so you get what you are paying for. Note: not the theoretical or claimed level but the actual level.

The addition of CSL will generally improve the fermentability but you will probably need the addition of enzymes and this adds to cost. Note that CSL generally has much better starch levels than molasses. Molasses is invert sugar which still has a fair amount of the sugar content remaining but from which a lot of the easily extractable sugar has been removed. A lot of the sugar remaining is in the form of more complex starches so it is all not utilisable. Again the use of enzymes can help remarkably. Hope this is some help.

B.r., David

Randy writes ...

with molasses you wont need to add sugar. Molasses is sugar in the liquid form. Brown Sugar is an economics alternative. It may be less expensive that molasses. You will have to adjust your mixture with water to get the brix (sugar content) number that you want. You should know that there are more than one type of molasses. The kind made from sugar cane is clear. The kind made from sorgham or a similar plant is darker. I only have sorgham available to me here. But with a mill located only a few miles away, it does have a cost effective angle for me. I found a link about the processing of sorgham into molasses syrup if you want to read it. It is interesting in that it describes the temperatures that the sysrup is added to storeage containers to prevent fermentation. It also describes the addition of enyzmes to convert starch to sugars and to invert sucrose to glucose and fructose. http://www.ca.uky.edu/agc/pubs/agr/agr123/agr123.htm.
One thing to keep in mind though is that you wil need to gently stir the fermentation buckets daily to keep the syrup in suspension.

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