yeast

15 Articles

From Sugar To Ethanol Fuel With A Little Microbial Help

June 30, 2026 by 65 Comments

In these trying times it seems appropriate to work through some ‘what if ‘ scenarios, such as the local gas station suddenly not having any more gasoline to sell you, or said gas station ceasing to exist altogether. In that case it can be incredibly useful to be able to create your own gasoline alternative in the form of ethanol. As demonstrated by [Hyperspace Pirate] in a recent video this process is fairly straightforward once you have procured an appropriate feedstock, such as here sugar (sucrose).

Although baker’s yeast (Saccaromyces cerevisiae) is more commonly associated with the production of ethanol-laced drinks, there’s nothing that says that you cannot distill out the approximately 10-15% ethanol that results from a yeast feeding frenzy and resulting waste products.

How to do this distillation step is explained in the video, with the mixture heated and put through a self-made reflux column to deal with the fact that the water/ethanol mixture is an azeotropic mixture, meaning that a lot of water is expected to make its way out of the condenser along with ethanol without this measure to condense as much of the water vapor before it can make its way to the top of the column.

Ultimately the conversion rate of plain white sugar to ethanol is about 54%, with the rest turning into CO2. With an appropriately converted combustion engine for running on 100% ethanol, it runs pretty well, though the final cost per liter of ethanol will heavily depend on your feedstock.

With the full costs of the electric heater of the distillation column taken into account – at 2.57 kWh/L – as well as the cost of the off-the-shelf sugar, [Hyperspace Pirate] with his Florida kWh cost of $0.12 paid around $2.62/L, or $9.91 per gallon. Even with how much prices at the gas pump have shot up recently, you’d pretty much need to find a free source of feedstock and otherwise optimize the process for it to make much sense, even in this economy.

That said, it’s crazy that the world of Mad Max doesn’t run on ethanol. If tomorrow a certain bubble were to implode and the global economy fell apart as a result, producing bioethanol would seem to be a highly marketable skill.

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Big Chemistry: Fuel Ethanol

May 21, 2025 by 73 Comments

If legend is to be believed, three disparate social forces in early 20th-century America – the temperance movement, the rise of car culture, and the Scots-Irish culture of the South – collided with unexpected results. The temperance movement managed to get Prohibition written into the Constitution, which rankled the rebellious spirit of the descendants of the Scots-Irish who settled the South. In response, some of them took to the backwoods with stills and sacks of corn, creating moonshine by the barrel for personal use and profit. And to avoid the consequences of this, they used their mechanical ingenuity to modify their Fords, Chevrolets, and Dodges to provide the speed needed to outrun the law.

Though that story may be somewhat apocryphal, at least one of those threads is still woven into the American story. The moonshiner’s hotrod morphed into NASCAR, one of the nation’s most-watched spectator sports, and informed much of the car culture of the 20th century in general. Unfortunately, that led in part to our current fossil fuel predicament and its attendant environmental consequences, which are now being addressed by replacing at least some of the gasoline we burn with the same “white lightning” those old moonshiners made. The cost-benefit analysis of ethanol as a fuel is open to debate, as is the wisdom of using food for motor fuel, but one thing’s for sure: turning corn into ethanol in industrially useful quantities isn’t easy, and it requires some Big Chemistry to get it done.
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Why Do Brits Drink Warm Beer?

August 16, 2022 by 152 Comments

Traveling through mainland Europe on a British passport leads you to several predictable conversations. There’s Marmite of course, then all the fun of the Brexit fair, and finally on a more serious note, beer. You see, I didn’t know this, but after decades of quaffing fine ales, I’m told we do it wrong because we drink our beer warm. “Warm?”, I say, thinking of a cooling glass of my local Old Hooky which is anything but warm when served in an Oxfordshire village pub, to receive the reply that they drink their beers cold. A bit of international deciphering later it emerges that “warm” is what I’d refer to as “cold”, or in fact “room temperature”, while “cold” in their parlance means “refrigerated”, or as I’d say it: “Too cold to taste anything”. Mild humour aside there’s clearly something afoot, so it’s time to get to the bottom of all this. Continue reading “Why Do Brits Drink Warm Beer?” →

Who Needs Yeast When You Have Lab Equipment?

March 26, 2022 by 32 Comments

This particular story on researchers successfully making yeast-free pizza dough has been making the rounds. As usual with stories written from a scientific angle, it’s worth digging into the details for some interesting bits. We took a look at the actual research paper and there are a few curious details worth sharing. Turns out that this isn’t the first method for yeast-free baking that has been developed, but it is the first method to combine leavening and baking together for a result on par with traditional bread-making processes.

Some different results from varying the amount of pressure released during the baking process.

Basically, a dough consisting of water, flour, and salt go into a hot autoclave (the header image shows a piece of dough as seen through the viewing window.) The autoclave pressurizes, forcing gasses into the dough in a process similar to carbonating beverages. Pressure is then released in a controlled fashion while the dough bakes and solidifies, and careful tuning of this process is what controls how the bread turns out.

With the right heat and pressure curve, researchers created a pizza whose crust was not only pleasing and tasty, but with a quality comparable to traditional methods.

How this idea came about is interesting in itself. One of the researchers developed a new method for thermosetting polyurethane, and realized that bread and polyurethane have something in common: they both require a foaming (proofing in the case of bread) and curing (baking in the case of bread) process. Performing the two processes concurrently with the correct balance yields the best product: optimized thermal insulation in the case of polyurethane, and a tasty and texturally-pleasing result in the case of pizza dough. After that, it was just a matter of experimentation to find the right balance.

The pressures (up to 6 bar) and temperatures (145° Celsius) involved are even pretty mild, relatively speaking, which could bode well for home-based pizza experimenters.

Open-Source Insulin: Biohackers Aiming For Distributed Production

August 23, 2021 by 76 Comments

When you’ve got a diabetic in your life, there are few moments in any day that are free from thoughts about insulin. Insulin is literally the first coherent thought I have every morning, when I check my daughter’s blood glucose level while she’s still asleep, and the last thought as I turn out the lights, making sure she has enough in her insulin pump to get through the night. And in between, with the constant need to calculate dosing, adjust levels, add corrections for an unexpected snack, or just looking in the fridge and counting up the number of backup vials we have on hand, insulin is a frequent if often unwanted intruder on my thoughts.

And now, as my daughter gets older and seeks like any teenager to become more independent, new thoughts about insulin have started to crop up. Insulin is expensive, and while we have excellent insurance, that can always change in a heartbeat. But even if it does, the insulin must flow — she has no choice in the matter. And so I thought it would be instructional to take a look at how insulin is made on a commercial scale, in the context of a growing movement of biohackers who are looking to build a more distributed system of insulin production. Their goal is to make insulin affordable, and with a vested interest, I want to know if they’ve got any chance of making that goal a reality.

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Spider Silk, Spider Silk, Made Using A Strain Of Yeast

November 6, 2020 by 25 Comments

Companies spend thousands developing a project for the market, hoping their investment will return big. Investing like this happens every day and won’t shock anyone. What may surprise you is someone who spends more than a decade and thousands of their own dollars to make an open-source version of a highly-marketable product. In this case, we’re talking about genetically modified yeast that produces spider silk. If that sounds like a lead-in to some Spiderman jokes and sci-fi references, you are correct on both accounts. [Justin Atkin] had some geneticist work under his belt when he started, so he planned to follow familiar procedures like extracting black widow DNA, isolating and copying the silk genes, and pasting them into a yeast strain. Easy peasy, right? Naturally, good science doesn’t happen overnight.

There are a few contenders for the strongest spider silk among which the golden silk orb-weaver gets the most attention, but the black widow’s webbing is nearly as strong, and [Justin] is happy to wear black widow inspired bling, whereas the golden orb-weaver looks like it crawled out of Starship Troopers. His first attempt to extract DNA starts with a vial of preserved nightmare fuel spider specimens because that is a thing you can just go online and buy. Sadly, they were candied in alcohol, and that obliterates DNA, so he moved to dried specimens from breeders, which also failed to produce results, and those were just the landmark hangups.

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Yeast Is A Hot Commodity; Brewing And Breadmaking During Lockdown

April 13, 2020 by 69 Comments

In the recent frenzy of stocking up with provisions as the populace prepare for their COVID-19 lockdown, there have been some widely-publicised examples of products that have become scarce commodities. Toilet paper, pasta, rice, tinned vegetables, and long-life milk are the ones that come to mind, but there’s another one that’s a little unexpected.

As everyone dusts off the breadmaker that’s lain unused for years since that time a loaf came out like a housebrick, or contemplates three months without beer and rediscovers their inner home brewer, it seems yeast can’t be had for love nor money. No matter, because the world is full of yeasts and thus social media is full of guides for capturing your own from dried fruit, or from the natural environment. A few days tending a pot of flour and water, taking away bacterial cultures and nurturing the one you want, and you can defy the shortage and have as much yeast as you need.

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