There has been some speculation over the efficacy of instant bakers yeast in producing ethanol elsewhere on these pages. So I’m reporting my results here for what its worth.


Mixed the following:

10L clarified “sour mash”, i.e. that what was left in the kettle from a previous distillation without the nasty bits that gravitated out.
2 L bottled water.
2.5 kg cane sugar.
Pinch of Nutrifeed (horticultural/hydroponic salts)
Pinch of MgSO4
Vit B tablet
Teaspoon of NaHCO3 as buffer
10g (one packet) of instant yeast.

I’ve measured the SG using a 10ml A grade pipette and a jewellery scale, and found the fresh mix to be 1.082 kg/L.


Two weeks hence, the SG measures 1.022 kg/L. The decrease in density is presumably due to the conversion of the sugar into C02 and ethanol via separate metabolic pathways. According to this nifty calculator, I can expect around 7.9% alcohol based on the SG measurements.

I’ll let the mash sit for another day or three until the fizzing peters out. Once distilled, I’ll update this thread with some more numbers to see if the yield was as predicted.

Not too clear what the “sour mash” is, and all those other arcane ingredients I do not currently have access to. I’m told a teaspoon of Marmite works well as food for the yeast. Someone also told me one should add sugar every day or two, and stir the mixture. I tried that because I think I may have started with too little sugar. I didn’t actually measure it; just guestimated a cup or cup and a half per two liters of water, and then added half a packet of yeast. With that mix, after four days or so, the fermentation pretty much stopped.

The resultant drink is quite delicious, particularly when chilled, with a sweet-sour taste. But no bubbles remaining, and it doesn’t taste of alcohol. After a few glasses it seems to have a relaxing effect, which is why I estimate the alcohol content at no more than two percent or so, but also not zero. Given that fermentation produces alcohol, and much of the sweet taste of the original is gone, there surely must be some alcohol in there.

Now with a new batch I have managed to extend the fermentation to five days by adding some sugar and turning the bottle end over end to mix two times a day or so. I’ll taste it this evening and see if there’s any difference.

That makes perfect sense. What is Marmite if not hydrolysed yeast parts? You’re probably giving them a scrapyard full of amino acids in the right ratio.

Well, the new batch did not taste much different from the previous one. Perhaps a bit too sweet; I think not all the sugars were converted. But once again with a certain relaxing effect. I’ll keep at it and see what happens.

I have an experiment, bound to fail, but I’m having a go nonetheless…

Mead: Honey, water, some tea, handful of raisins (chopped). That’s it, No yeast added. Amounts to just over a gallon. OG: 1.085

I put it in a cool dark place day 1 (Saturday) but found it too cold (got down to 10C). Moved to a more room temperature spot, I guess summer’s over. I’m expecting the start of fermentation to take a while.

Fermenting foods I’ve had much luck this way, but I’m worried, so we’ll see how this works out. Will let ya’ll know. (Although time-to-drink for mead is months, but I hope at least to have fermentation in about a week).

Here are the results of the distillation based on the ferment described in he OP. Seems that one can achieve around 10% ethanol with instant bakers yeast.

[tr][td]Fraction ID Volume(ml) %ABW Et-OH (g)[/td][/tr]
[tr][td]Head 60 60 36 [/td][/tr]
[tr][td]Heart A 1 000 55 550[/td][/tr]
[tr][td]Heart B 1 000 48 480[/td][/tr]
[tr][td]Tail 2 000 28 560[/td][/tr]

[tr][td]Previous tail added to still -400[/td][/tr]

[tr][td]Total out 1226[/td][/tr]

[tr][td]Ferment 12 000 10.2 [/td][/tr]

However, from the video linked to by brianvds elsewhere, it may be that the concern with bakers yeast is not so much if it will produce alcohol, but rather its effect on the taste of the beverage. I’ve grabbed a punnet of red and white grapes during my balls-to-the-wall shopping excursion yesterday. Will see if its possible to get an auto ferment going, as in the video.

Not me though. After five days the fermentation stops, whatever I do, with no appreciable alcohol in the brew. Mind you, I did notice something strange yesterday. Because there is very little in the way of sediment, I don’t mind drinking the brew to the last dregs, and when I drank those I suddenly noticed a very strong taste of alcohol. Apparently all the alcohol goes to sit in the bottom of the container. And this might explain why I’m having trouble: the yeast sinks to the bottom, where it produces a high level of alcohol that ends up killing it. But the higher layers of the brew remain largely alcohol-free.

It might work better if I regularly mix the brew. Next time I’ll add a bit of Marmite to feed the yeast, and make a point of mixing every hour or two.

I did give it a stir every day, yes. Although strictly speaking one shouldn’t let air in if I understand the authorities correctly. And you know the distiller is a seasoned authority if his name carries the appellation “Oom”.

Well, I use 2L Coke bottles, which do not let all that much air in to begin with. Anyway, I’ll try it out and see. Even with little alcohol, I find the resulting drink quite delicious.

It didn’t work out that way. Nothing BAD happened to it but it never got fermenting. I’d had a go with some grapes too but also naught. So I added some baker’s yeast to the grape juice. Within about a day it was producing CO2, so I pitched a spot of the grape juice into the mead. Now it’s bubbling away happily. There was maybe 1 spot of gunkyness on the surface when I found it but I scooped it out and hopefully the ferment will keep stuff from getting worse. “We shall see”.

In the meantime I’ve started a 10l batch of pineapple brew too: I still have booze but it won’t last forever, so, why not?

I’m honestly enjoying this. I may have to acquire some copper tube if things keep going like this…

I think I have been using too little sugar. Yesterday I did something I should have done to begin with: took a sip of my sugar solution before adding yeast. And it struck me as rather bland. For the next batch I’ll start with much more sugar. I also accidentally added more yeast than usual, and after an hour the thing was positively boiling, with foam pushing out of the bottle. SO perhaps one should also add more yeast?

Don’t know, but I’ll try that out with the next batch: much more sugar and perhaps a whole 10 g packet of yeast per bottle, rather than only half.

I think it’s the sugar. I doubt you need a whole 10g of yeast per 2l bottle. I use half of that on 10l batches.

I ended up using perhaps 3/4 of a packet, on a solution containing much more sugar. Judged by the amount of bubbling, thus far it is making little difference. I am increasingly of the opinion that baker’s yeast will simply not yield more than 2% alcohol or thereabouts, and those who say differently are fooling themselves. :slight_smile:

You’re not trying to make a Jacuzzi: It should bubble away slowly for a longer time… Not more vigorously. This is why I thought adding more yeast is probably a waste of time. The yeast makes alcohol out of sugars: The more sugar, the more potential for alcohol. No sugar, lots of yeast = no alcohol. Lots of sugar, little bit of yeast = alcohol (yeast multiplies, sugar does not).

Be that as it may, I don’t have an OG for the pineapple beverage as I reckoned a lot of the sugar isn’t in dissolved form anyway. Luckily for the mead I do, when fermentation slows down I’ll take another measurement and can then take a guess at the alcohol content.

Well, I’ll have to see how long this one will keep on bubbling. Thus far, around day five, the bubbling pretty much stopped, with very little alcohol present. Adding sugar and regularly stirring seems not to make any difference.


Oooo … nice. Posh yeast once again available to us mortals.

My brother in law in the western cape makes use of this supplier. He’s been swept up in the hobby for a few years now. Makes a pretty decent stout.

I have seen videos on YT about harvesting yeast post-ferment and storing it. People of the prepper mindset may choose to perpetuate instead of sourcing going forward.

Yes, the products from that Cape Town company are rather on the expensive side.

In the meantime, someone online told me he is mystified by my report of my fermentation just stopping after five days. But he thinks that conceivably the magic ingredient might be raisins. Well, I’ll give it a try if and when I can get hold of raisins…

Probably a stupid question but is it receiving sunlight?