Large scale ethanol production from waste products is well established both here in Europe and in the US but no one seems to be doing it on a small scale suited to a home brewer.
I have been making biodiesel for 2 years now and am very happy with it. I use only liquid oil for processing and keep the yellow grease for heating my workshop. See the topic "Military Heater for sale on Ebay" for details on how yellow grease can be used as a clean heating source. I have also been using the same burner to power my methanol recovery still.
Ive just built a larger still( 150 litres) which works from the same free heat source.
Im now looking into the possibility of using the still to produce ethanol from waste products that I can easily get locally. I can get large quantities of Cheese whey, waste bread products, spoiled fruit, all of which contain either fermentable sugars or convertible starches. Not only are they available but I would be paid to haul them away.
There is nothing new or especially difficult about the process, but what I need to devise is a system that is labour saving and convenient preferably that can be built from easily available materials, oil drums, standard plumbing etc.
Does anyone out there know of sources of information that might be of use to me or do you have any ideas or experience you might share.

Does "small scale" mean just a few gallons a month or a few HUNDRED gallons a month?

A general web search for "make your own fuel" or "make E85 fuel" will find a lot of info.

This links to an old website about making ethanol for E85 fuel, it has a lot of interesting info but the originator of the page died a few years ago so it is not totally current.

Unfortunatly, this venture will likely be pretty labor intensive if using basic concepts. I Have seen basic legal commercial wisky stills that consist of nothing more than a couple of 10,000 gallon open topped steel tanks, vat strainers and filtering setup, pumps, old fire hose for plumbing, and a basic still.

Many local beer breweries give free tours of there breweries, these tours have given me many ideas into how those already producing ethanol have approached the process, the free beer tasting is a plus.

For any reasonable amount of ethanol production you are going to need a bit of space as you will have to mash at least 10 times as much fermentation fluid as the amount of ethanol you wish to produce. You are also going to have a LOT of yeast and left over feedstock glop to get rid of. My 5 gallon glass carboys of home brewed beer, wine, and mead produce a 2-3 inch deep layer of yeast, fermenting a few hundred gallons will grow a lot of yeast.

To start - It may be more conveniant to visit all your local pubs and such, even brewries. Collect all the waste drinks they pour out into there bar sink, or the couple gallons of old beer that gets dumped out of each returning beer keg. This would allow you to concentrate on the distillation of the ethanol rather than the fermentation.

What legal restrictions to distilling alcohol are in place in Ireland, Last I checked, here in the US we are restricted to less than 5000 gallons alcohol per year as hobby fuel distillers.

Hello Tim, my aim is to produce enough ethanol to run a second car, a Volkswagen Polo or other small car. Based on a mileage of 20000 mile per year and 40 mpg Ill need about 10 imperial gals or 45 litres per week. This means processing 450 -500 litres of feed stock every week.

Ive looked at Robt Warrens site, in fact I have a copy of his still plans which are very good. My own still makes use of some of his ideas. I dont intend to run on E85. 170% proof ethanol is much more economical of energy and easier to make. It means converting the carburettor of the polo but that would not seem to be a big problem.
Ive looked carefully at how distilleries and breweries operate but their priorities are very different to someone making alcohol fuel. It was still worth the visit for the free whiskey.

My oil burner is capable of heating about 150 litres to a rolling boil but not more. The burner is really cheap $20 dollars on Ebay so I have bought 4. My idea at present is to have four steel 55gal oil drums, each with a burner mounted underneath. Each drum can serve as a cooker, a fermenter and a still depending on what lid is put onto it. The cooker lid would have a drill mounted mixer, the fermenter would have a cooling coil, a mixer and a fermentation lock, the still lid would have a reflux still head and a safety valve. This system should mean much less handling of feedstock, which as you say is a major problem.
I will should no problem with disposing of spent feedstock as a friend has a pig farm.

You idea of collecting waste drinks from pubs is a good one which I had not thought of before.I dont think I could get enough to produce all of my need but it would be a useful additive to the feedstock.
I have permission from the Revenue commissioners to operate a still producing denatured alcohol because of my methanol recovery. I dont know if there is a limit but Ill cross the bridge when I come to it. Thanks for your input.

10 imperial gallons/week, that is going to take a good bit of time to boil a hundred gallons of wort, I would expect about three 8 hr days a week would have to be allowed for this, I would think it would take several hours just to get 50 gallons of the sugar water up to the boiling point, then several more hours per barrel for running the still?

I have been running my 500CC 12 HP riding lawn mower on E85 ethanol all this summer, very good results, considerably more power and uses less E85 than it did gasoline, the oil has also stayed MUCH cleaner. The only adjustment I made to the carborator was to slightly increase the main fuel jet, luckily this engine has a carborator with a main jet that is adjustable rather than replacable. I LIKE alcohol as vehicle fuel..

Sounds like you have thought this through enough to give it a go, you will be the leading experimenter on this concept, at least in this discussion group.

I don't quite understand the verious uses of the barrels, why does the fermenter need a cooling coil, the fermentation should proceed faster if it is warm, also don't understand the term "cooker" unless this is referring to boiling the fermented liquid. I hadn't thought of a stirrer, is this to keep the solids from settling during boiling as a still. I would have expected the fermentation liquid would have been poured of the solids before heating the liquid for distillation.

I have been thinking about this same sort of process mainly using mesquite beans for the feed stock (30% direct suger, no mashing time needed to convert starch to sugar), I have a couple acres of Arizona desert that is covered with mesquite bushes. Reading indicates about 300 gallons of ethanol/acre from these. Once I build the equipment it could just as easily be used with other feed stock.

I have been heating two buildings with vegoil drip heaters over the last two winters, one is a similar burner as the military ones but even simpler (discussion here). I could use this sort of burner or more likely I will fuel a simple "roarer" type pressure burner (bigger version of a Coalman camp stove burner) fueled with the ethanol, much claner burn and plenty of heat.

How do you intend to remove the spent feed stock from the barrels?

For me time is not a big problem. Im in my workshop most days and the still or fermenter can be running in the background. I am concerned that the oil burner will take too long to bring 150 litres up to the boil. I may use an over the side immersion heater to boost the heat initially.

The cooker is to sterilize the cheese whey and to soften and break down the bakery waste. After boiling for 15 mins the cooling coil reduces the temperature quickly down to the temperature suitable for starch enzymes to work, then reduces again to the temp suitable for yeast. In larger vats the fermenting process can give off a lot of heat which can kill the yeast. I may need the cooling coil to keep the temperature under control. I wont know until I try a full sized batch.
I,ve read about mesquite but never seen it. In our climate Jerusalem Artichokes or Sugar beet would seem to be the best bet. I dont really want to get into growing my own feedstock as there seems to be so much waste material available. I recently made enquiries at food factory near me that makes oven ready french fries. They would be happy to let me have half a ton of potato skins a week!
I intend to braze a 2 or 3 inch pipe and valve to the bottom of each tank for easy emptying.
Small air cooled engines seem to work well with alcohol. Years ago I used to drive a Citroen 2CV Car with a 500cc twin cylinder engine. I bet it would run on alcohol no problem but it was slow I couldnt bear to drive one now.

Here is a pic of my workshop stove. I start it on biodiesel for about an hour until the small tank on top heats up and melts the solid fat. Then I turn off the biodiesel and trickle feed the hot fat into the burner via a peristaltic dosing pump. It uses about 1 litre of fuel per hour and puts out about 10K watt of heat. I clean it once a week with a vacuum cleaner, 5 minute job.
Although liquid wvo is scarce around here, I only get just enough to fuel my car with biodiesel, I can get all the solid grease I want.

Ive completed two trial runs with whey/bread waste and whey/potato waste. The first was much more sucessful. I achieved 33% fermentable sugars and 11% alcohol. The second had 17% sugars and is fermenting as we speak. I would expect only 7% alcohol.
If I can consistently achieve over 12% alcohol this is going to be feasable.
My batches will be 170 litres so each batch will yield about 20 litres of 85% pure ethanol. I have modified an old toyota corolla to run on this mixture of ethanol and water so hope to be running by Christmas.

Déise how are getting along with the ethanol
Instead of heating 150lt of whey couldn’t you heat a small amount in a continuous stream and evaporate the alcohol this way then do a second cut for the good stuff just a thought

Im using an Alaska burner with yellow grease as fuel to power my still so energy consumption doesnt matter, in fact Im under pressure to use up yellow grease.
Im now starting my fourth 20 litre trial run. The third was whey/waste bread and it achieved 30% sugars and 12 % alcohol which is what Im after. This next batch will use water instead of whey to see how much the whey contributes. The enzyme used to convert the whey is the most expensive additive and I want to be sure that I need to use whey. I also want to experiment with using less enzyme but leaving it longer to work,overnight perhaps. My 200 litre batch outfit is almost ready for action.

Alaska burner -- I assume these are the military tent heater burners, if so, based on reading through that discussion it seems they perform best (blue flames) if the combustion air is drawn up through the holes in the side of the bottom burner pot rather than in across the flames, to insure this the flame section is closed off to external air. This would seem to take something more than simply placing the burner unit alone under a seperate barrel, did you build a seperate burner containment tank around each burner to keep air from the flame section, or are you simply placing the burner unit under the barrel and accepting an orange smoky flame.

Enzyme -- I don't think these are consumed in the process as chemicals are, can you recover the water containing the enzyme and recycle it to the next batch of wart?

Have you had to use the cooling coils yet. My largest fermentation batches have only been 5 gallons but I never noticed any heat being produced during fermentation.

I assume you are getting the whey from a bakery, what exactly are you getting from them? What should I inquire about is what I am asking. I dont have a potato chip plant here, but we have two bakeries. Most people here are clueless so I need to be quite specific.

Time isnt an issue for me, finding enough feedstock for the stills is, particularly this time of year.

Im sorry I didnt reply sooner Tim. I didnt get a notification of your message.
You are absolutely right about the air supply to the burner. It will never burn cleanly if air is not forced to flow in from underneath. If you click on the picture earlier in this topic it will take you to my Image shack. Click on more images and you will see pics of the stove under construction.
In my new still and also on a water heater I have built the burner plugs into the bottom of the drum using a simple bayonet mount. This makes it easy to remove it for cleaning.
I had not thought of enzyme recycling before and will have to look at it.
The cooling coil has proved useful for reducing the temperature of the mash quickly at the cooking stage. This saves time and reduces the opportunities for bacteria to go to work on my precious sugars. However I have found that even a 200 litre fermentation needs a little extra heating, not cooling. The average temperature is around 5 degrees C here so it may be a different story in summertime.

Thumpin455,I get my whey in liquid form from a cheese maker. He has to dump 1000gals of it every week. The waste bread comes from a local supermarket chain. I have found from my trials that potato waste wont work. It requires a lot of cooking which uses a lot of energy and it contains about 80% water which makes a very dilute mash, requiring even more energy to distill. Bread waste is only 10- 20% water and is already cooked. It is definetely the way to go.
From my trials I estimate that every 100 litres of mash will yield 10 litres of ethanol fuel and 60 kg of distillers grains. This stuff is highly edible. My chickens prefer it to their layers mash. It may well have a value equal to the fuel and could make small scale ethanol production profitable rather than just viable.

On the subject of edibility you have to be careful what you add to the mash if you want it to be safe to feed to animals. Acetic acid rather than the cheaper sulphuric and sodium carbonate rather than the much stronger sodium hydroxide.

imake - I have been doing a bit of web searching lately about small scale ethanol brewing, I had made a good amount of beer in the past but always used grains that were already malted as additives to malt syrup so never actually did the complete process needed to convert starch into sugar. I found an "Alcohol Fuel Manual" (HERE)
that was published by Mother Earth magazine 30 years or so ago, it does a nice job describing the process. They indicate cheese whey alone should produce around 2 1/2 percent sugar and they say that it does NOT need any enzymes to produce the sugar? I now have a much better understanding of how and why the enzymes (a-amylase - gluco-amylase) are used.

The ME manual is basically about using corn as the grain, that is what I am considering here, but I like your idea of old bread even better, it sounds like it produces just as much sugar as raw grain and there has to be a LOT of it available about everywhere without spending $4.00 per bushel for corn. Several bread bakeries around here have "day-old bread" outlets but I am sure they don't sell it all, there waste likely goes directly to the landfill, I will check into this.

The ME fuel manual describes using a-amylase enzyme in the pre-boil heat for 15 minutes to get the starch-to-sugar conversion started, then boiling the grain/water for 30 minutes to liquify the starch, then adding more enzyme once the boiled mash temp dropped back to the correct cooler temperature, not sure which enzymes are used, a-amylyase or gluco-amylase, maybe both, to convert the starch into sugar, and then the un-fermentable long chain sugars into fermentable short chain sugars. ME originaly sold there own "brewing powder", (not sure what it actually was made up of) to complete the conversion of starch to un-fermentable long chain sugars (a-amylase conversion of starch) that is then converted into fermentable short chain sugars (gluco-amylase conversion)? I am not completely clear on just when each type of enzyme is used when, apparently the a-amalyse converts the starch into long chain sugars that yeasts CAN NOT convert to alcohol so you need to use the gluco-amylase enzyme after the a-amylase step to complete the conversion of the un-fermentable long chain sugars into fermentable short chain sugars. Other brewing web sites refer to the a-amylase step but don't mention the gluco-amylase enzyme at all, are you using both these enzymes to totaly convert the starch in the bread into fermentable sugars?

There is also referance to using the "Iodine test" to tell when all the starch has been converted into sugars, do you do this test.

Recycling the enzymes - Researching the use of the amylase, they refer to these becoming "denatured" (apparently this means the enzyme is permanently de-activated) once the temp of the fluid is raised above some temp that is less than the temp needed to boil the mash, this seems to indicate that any enzyme added prior to the boil can not be recycled but enzyme added after the mash has cooled should still be available to use as the enzyme for the pre-boil step in the next batch? Unfortunatly, if the distillation process raises the temp of the mash up to boiling it will denature all the enzyme in the mash so it will require fresh enzyme for each batch.

Is it possible/practical to drain the liquid off the distillers grain after the distillation, what is the consistency of the mash when using bread as the feed stock, is it liquid or some sort of paste, can free liquid be drained from the bread-based mash? Is all the bread converted to a liquid, what is left over once you get this type mash completely through the process?

Ebay currently has 1/4 pound quantities of a-amylase for $8.00 U.S., plus shipping. Brewing sites offer it for $1.00 to $5.00 for a few ounces but I have not yet found a retail outlet selling small quantities for the gluco-amylase (sometimes refered to as bata-amylase, I think these are the same anyway).

How long does it take to bring the verious sized batches to a rolling boil, this seems to be the step that takes the most energy. The ME manual says to use 30 gallons of water for each bushel of corn, this should yield around 2 1/2 gallons of alcohol, it takes a LOT of heat to boil 30 gallons of water for 30 minutes, sorta makes the process impractical unless you have a source of free heat, we have LOTS of free wood to use in this step but controlling the temp of the mash using a direct wood fire will be the challenge. I could use veg but I have better uses for that, may try used engine oil in a syphon or babington style oil furnace burner (modified from a normal home furnace pressure type oil burner)? May be easier to use one of the military tent heater burners with the used motor oil even if it needs to be cleaned often, may be worth buying one of these burners for some testing. I suspect one of these would heat a 55 gallon mash barrel just fine but don't know how well it would heat a 400 gallon tank of mash?

Going to need a LOT of controllable heat if processing 300-500 gallon batches (20 to 35 gallon yield of ethanol/batch), some type of oil burner seems the most practical. I have several round horizontal steel 500 gallon bulk farm fuel tanks now and they show up regularly in my local salvage yard, with a bit of modification these should work fine for processing 300-400 gallon batches (need some headspace for the vigorous boiling). It may be possible to develop an indirect heating method using a wood fire to directly heat a tank of veg oil, or used motor oil, or possibly glycol, then controlling a pump to move this hot fluid through heating coils in the brewing tank.

Not too surprised it takes a bit of heat to keep the fermentation process up to temp, I never saw any heat produced during my 5 gallon batches of home brew beer. Heat is not needed if you can accept more time, true lagger beer fermentation deliberately takes place at just a couple degrees above freezing, type of yeast used needs to be researched for there temp characteristics.

Hi Tim, all of my batches so far have been 20 litre so I cant claim to know exactly how to scale up but I have some ideas.
The whey will benefit from an enzyme called lactase. Without it I get 2 % sugar, with it I get 5%.
I heat the whey up to 50C and add the lactase. after an hour I continue to heat up to 85C. I add the bread and mix with a paint stirrer. It makes a very thick paste. I add the amylase and it instantly liquifies. I cool to 37c in two hours and add the gluco-amylase and cool for 2 hours to 25c. I add the yeast and fit a fermentation air lock. Its ready for distillation in 4 days.
For scaling up I had thought of a steel tank mounted on top of a brick built fire box. I could use salvage wood to do the initial heat up. The close control is needed when cooling. I thought a water cooled copper coil in the tank would work
After fermentation the beer will be filtered through fine filter socks to separate the grains. It would then be distilled in 150 litre batches using a still powered by an alaska burner, perhaps with an electric immersion heater to speed up the initial boil time.
I got my enzymes from Novo Industries. I contacted them, told them what I was doing and they sent me free samples of one litre each which has been more than enough for my tests. I also got free samples of Ethanol Red yeast ( up to 18% alcohol) from Fermentis but I will probably stick to using ordinary brewers yeast because of the cost.
Its hard to see how I might recover the enzymes. they are dissolved in the beer and distillation will denature them.

Enzymes and yeast -- Thanks for the info, I tried to find a-amylase at a coupler local brewing supply places, no luck. I did find small packets of dry yeast that survive 18% alcohol, each packet is for 5 gallon brews and cost 70 cents U.S. (Lalvin wine yeast web page).

It is fairly easy to stretch your yest by growing larger quantities, the yeast needs air for this so you don't use a brewing lock. this links to some info, this links to a brewers discussion page about how they do it in the real world.

I would think you could also recover the bottom inch of the fermented mash before heating it for distillation, most of the yeast should still be active unless your alcohol yield was well above your estimate. The yeast will likely mutate after doing this a few times but for fuel ethanol it won't matter if the flavor of the yeast changes, worst case is that the alcohol tolerance of the yeast will drop over lots of re-use.

There is a new commercial ethanol plant about to go on-line in a neighboring town, I will try to contact there chemist, may be able to score quantities of yeast and enzymes through them?

Found a web retailer source (HERE - milehidistilling.com) for both alpha-amylase and glucoamylase, one pound bags of either one are listed for $14.99 plus shipping.

They also list a 18 ounce (500 grams) bulk package of yeast that will survive to 21% alcohol on THIS page for the same $14.99 plus shipping.

imake - Question about reuse of mash water -- In an earlier post you indicated you were considering making a test between a mash with whey/bread and water/bread, did you do a batch with just water and bread? If so, I would have expected the mash to consist almost only of sweet water after the enzyme treatment, since bread is almost entierly starch I would have expected it to be almost entirely converted into sugar and then all of the sugar to have been converted to alcohol in the fermentation, I would have expected the mash to then look like clear water with a couple inches of yeast laying on the bottom of the container, is this any where near correct. I am wondering if the water used in this bread-only mash can be reused directly or can it be strained and reused, or is it full of something that makes it too cloudy/cruddy to be reused? Could the spent mash water from an all-grain mash simply be strained through a cloth and reused?

If the mash water can be reused the percentage of sugers in any one mash would not need to be held to a level that the yeast can survive (unless you are growing yeast for later use), any sugar that is not converted in one mash will still be present in the recycled spent mash water and add to the sugar produced in the next mash cycle. The cost of needing to add new live yeast in each mash batch may want to be balanced against the cost of reusing live yeast left from a previous lower percentage of alcohol batch verses producing the max amount of alcohol in every batch?

Bread mash - You indicated you added bread and stirred til you have a very thick paste, how much bread do you have to add to the 20 liters of liquid to get to the thick paste stage, and what percent of sugar is this likely to produce?

In the Mother Earth manual they call for a 30 minute rolling boil of the mash 15 minutes after adding the first dose of a-amylase, this boiling is apparently to insure complete conversion/liquification of all the starch to sugar and also sterilizes the mash to kill any mold/fungus/bacteria that might interfere with fermentation (this may only be needeed when using whole unprocessed grains that are prone to fungus?), it sounds like you DO NOT increase the temp to a boil but instead allow the mash to start a slow cool to the temp needed to add the glucoamylase, am I correct with this analyses?

Ethanol red yeast -- Reading about this it looks like it's big claim to fame is that it can be used at up to around 35 deg c (95 deg f) temps and 18% alcohol, there are other yeasts that will work to even higher percentages of alcohol but don't survive these high temps, I assume the higher temps cause faster fermentation so the fermentation time is reduced a bit, probably not a real concern for us small scale brewers. The retailer I linked to in the above post has yeast available that survive to 21% alcohol, and it is available in 500 gram or 25 kg bulk quantities. Reading there description they refer to this yeast as producing 14% alcohol in 3 days or 21% alcohol in 5 days so I assume the fermentation slows down as the amount of alcohol percentage increases, this may be caused by the weaker yeasts dying as the alcohol percentage increases causing less live yeast to be available to finish the fermentation?

My best result so far has involved 6Kg of bread and 15 litres of whey. This yielded 20% fermentable sugar and 9% alcohol.
I did do a water/bread batch but found the sugar yeild too low and didnt bother to ferment it. I cant remember that the mash looked very different from the whey/bread mash.
With alcohol yields of around 10% ordinary brewers yeast works fine and there is no need to spend extra on turbo yeasts etc.
I dont have to boil the whey /bread mix because the bread is already cooked. This is a big saving on energy. Combined with good hygiene, 85C is enough to weaken any bacteria and moulds, giving your yeast a head start.
I have read up on yeast recycling but dont want to use it during my tests in case it would affect the yield results.