[HN Gopher] Rwandan scientists develop local yeast for banana wi...
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Rwandan scientists develop local yeast for banana wine-makers
Author : PaulHoule
Score : 180 points
Date : 2025-02-08 19:09 UTC (2 days ago)
(HTM) web link (phys.org)
(TXT) w3m dump (phys.org)
| bcatanzaro wrote:
| "The team looked for a fermenting agent that could remain
| reactive in substances with a temperature of up to 370 degrees
| Celsius and alcohol of the recommended 16 percent per volume."
|
| My guess is that the reporter forgot a decimal point and meant
| 37.0 degrees Celsius. Because finding a yeast that actively
| metabolizes sugar at 370 degrees Celsius might be somewhat
| challenging.
| aDyslecticCrow wrote:
| Yiest that could survive in volcanic geysers is a bit
| terrifying to think about.
| tmoertel wrote:
| It turns out that the Yellowstone Supervolcano is actually
| over-risen bread...
| codesnik wrote:
| free kombucha!
| interludead wrote:
| Still, the research itself is pretty exciting. It's cool to see
| traditional methods getting scientific backing
| piuantiderp wrote:
| This made me snort my coffee, what backing was needed or
| lacking? Need peer-review to validate them?
| nxobject wrote:
| Consistency and reproducibility is important part of
| scientific backing, too.
| johnofthesea wrote:
| Optimal temperature for yeast in general is between 25-30C, for
| grape wine optimal fermentation is usually between 15-20C
| (white) 20-25C (red).
|
| So 35C is interesting. 350 would be too much even if it was
| Kelvin.
| throw-qqqqq wrote:
| Kveik beer yeast often works well far above 35C. Some
| reportedly tolerate into low 40s.
|
| I don't know of other yeasts that can do this though.
| giantg2 wrote:
| I was going to say, just throw some kiveik in it. That
| stuff is practically fool-proof
| nxobject wrote:
| Mmm, caramel sweet wine, perhaps?
| jojobas wrote:
| Especially given glucose decomposes under 200C.
| xattt wrote:
| New fermentothermal electricity power source discovered!
| gp wrote:
| 370 degrees Celsius? Hopefully a typo
|
| Last time I was in Rwanda I had banana wine. It comes in beer
| bottles.
|
| I think it's an acquired taste - I didn't have the acumen to
| acquire it myself.
| ReptileMan wrote:
| Fruit wines are tasty usually. But the hangover is on the next
| level.
| permo-w wrote:
| depends on the fruit and how many anti-oxidants managed to
| survive the brewing process
| skyyler wrote:
| almost entirely depends on how much water you drink, in my
| experience
| werdnapk wrote:
| Water is the secret that I wish a younger version of me
| knew about.
| Loughla wrote:
| College kids in my day just drank and drank and drank and
| learned to deal with hangovers.
|
| College kids today tend to alternate one alcoholic to one
| water. They don't really have hangovers.
|
| They're smarter than we were.
| throaway89 wrote:
| Frank the Tank!
| nxobject wrote:
| Quasi-mandatory orientation week training about safely
| drinking really worked - I know college kids who'll eat
| while they're drinking, and apparently they make make
| "BORGS" with electrolyte drinks mixed in too.
|
| I just wish they had training about all the avoidable
| mistakes you'll make in college relationships...
| sva_ wrote:
| I've heard stories of med students at my former
| university going on a saline solution IV drip to drink
| more.
| fragmede wrote:
| IV therapy is big business in places like Las Vegas.
| permo-w wrote:
| I find it bewildering that anyone ever didn't know about
| this. almost like not knowing sex causes babies
| taurknaut wrote:
| Pectin breaks down into methanol. Particularly fruit
| wines and liqueurs will end up with hyper-concentrated
| methanol. Water will help but cannot remove the pain of
| actually passing that methanol.
|
| Granted, it's not so bad with the first glass. But with
| three, be prepared for a nasty hangover. At least this is
| my experience with applejack. Professionally-made apple
| jack may be cleaned up more (I kind of hope it is).
| throwup238 wrote:
| It depends on the aging. The nasty metabolites that
| affect taste and cause hangovers are slowly converted to
| less nasty chemicals as the wine ages.
| jjcob wrote:
| I wish avoiding a hangover was as easy as drinking water.
|
| I get really bad hangover from some wines and beers, and
| no hangover at all from others. Haven't been able to
| figure out what the difference is. Wish I could just
| drink water to avoid it.
|
| However, 400mg of Ibuprofen helps a lot.
| werdnapk wrote:
| All wine is made from fruit.
| ReptileMan wrote:
| Unlike classical grape wines, the fruit ones are quite
| "wet". And sweet alcohol for reasons unknown causes the
| worst of the hangovers.
| mofunnyman wrote:
| It's for the same reason you feel dead after eating a
| pound of sugar, and compounded with extra dehydration.
| Take it from a former professional alcoholic, drink your
| water and take your B vitamins.
| throwawaymaths wrote:
| is it unknown? sugar competes with aldehyde
| dehydrogenase.
| PaulHoule wrote:
| Isn't "fruit" wine kind of a marketing term for "fruit
| flavored wine", that is "strawberry wine" is supposed to
| taste like a treat?
|
| The one alcohol that I've made in large quantities [1] is
| apple cider [2] which I've always made very dry, even
| though I perceive it has an apple taste, pear cider tastes
| like pears, even if it is dry.
|
| In sinosphere adaptations of classical Chinese stories like
| _Romance of the Three Kingdoms_ people talk about drinking
| 'wine' but my understanding is that what they drank wasn't
| made from grapes.
|
| [1] probably drank too much of it one December and might
| have started to get dependent
|
| [2] on my farm we have a few hedgerows that have apples
| that are good for eating, seedling apples (in some areas
| surrounded by hedgerows) are usually yucky for eating,
| although horses think they are fine and they are great for
| cider.
| zdragnar wrote:
| For fruit wines: you can ferment any fruit with enough
| sugar. They tend to be made sweet, as many fruits can
| have bitter or unpleasant flavors that come out when dry,
| such as strawberry. That said, one of my favorites was a
| dry raspberry that my dad made.
|
| The Chinese stories could be referring to rice wine, a
| spirit similar to sake. If the stories refer to regions
| along the Silk road though, they could easily also be
| referring to grape wine.
| PaulHoule wrote:
| The Chinese alcoholic drink that I think about today is
|
| https://en.wikipedia.org/wiki/Baijiu
|
| which might have exited in a prototypical form at that
| time.
| zdragnar wrote:
| That is a distilled spirit.
|
| Mijiu:
|
| https://en.m.wikipedia.org/wiki/Mijiu
|
| is what would be a rice wine. Wikipedia listed it going
| back as far as 1000 BCE.
|
| It is considered more of a wine than an ale presumably
| due to the alcohol content, the type of yeast used and
| how it is usually consumed, despite being a grain
| beverage (somewhat like barleywine only more so).
| PaulHoule wrote:
| Kinda like Japanese Sake?
| lmm wrote:
| > Isn't "fruit" wine kind of a marketing term for "fruit
| flavored wine", that is "strawberry wine" is supposed to
| taste like a treat?
|
| It shouldn't be, I'm sure there are companies who will
| sell that as "fruit wine" just as you'll get companies
| selling industrial alcohol mixed with grape juice as
| "wine" anywhere where that's legal, but a true fruit wine
| is made by fermenting that fruit.
| ChrisMarshallNY wrote:
| Ah ... it has been a long, long time, but I fondly
| remember imbibing _(and then, promptly, exbibing)_ that
| great, fruity vintage: _Mogen David 20 /20_.
|
| Toilet-hugging good.
| chongli wrote:
| Nope. Rice wine, sorghum wine, barley wine. Those are 3
| wines made from grains that I could name off the top of my
| head.
| dmurray wrote:
| Barleywine is a beer (it requires malting of the barley)
| marketed as a wine.
|
| Sorghum wine (baijiu) is a distilled spirit, closer to
| vodka, mistranslated as a wine.
|
| Rice wine (sake, mijiu) really does seem more like a wine
| than a beer, apart from the fact that it's made from
| grain. Not sure what is special about rice that makes it
| suitable for making wine.
| InDubioProRubio wrote:
| Not true, ever since we had advanced chemistry:
| https://en.wikipedia.org/wiki/Carbohydrate_synthesis
| gwd wrote:
| The phrase I've heard is "country wine" -- e.g., any
| alcoholic beverage in the ABV of wine (10-18%) but not made
| exclusively from grapes.
| b800h wrote:
| This is because pectin in the fleshier fruits will be
| metabolised into methanol, which isn't very good for you.
|
| Grapes are less of an issue.
| lambda wrote:
| The article mentions that it was provided by SciDev.net.
|
| Looking there you find the original article, and it has the
| correction to the right temperature:
| https://www.scidev.net/global/supported-content/rwandan-scie...
| culi wrote:
| > The team looked for a fermenting agent that could remain
| reactive in substances with a temperature of up to 37 degrees
| Celsius* and alcohol of the recommended 16 per cent per
| volume.
|
| > This article was edited on 29/01 to correct the temperature
| for fermenting to 37 degrees Celsius.
| tiahura wrote:
| Certain yeasts used in beer brewing produce an ester that is
| banana-like, especially when brewed at higher temps. It's often
| considered an off-flavor.
| DFHippie wrote:
| Now I'm really curious to taste banana wine.
|
| Banana is one of those flavors that some people love and some
| people really hate. Others in this category -- lutefisk, kimchi,
| certain cheeses -- make sense: their distinctive flavor is
| associated with decay. Why bananas, though?
|
| My grandfather was a banana hater. His observation on the topic:
| "I hate bananas, and I'm glad that I hate them, because if I
| liked them I'd eat them, and I HATE them!"
| sram1337 wrote:
| Bananas are a staple food crop in some parts of Africa.
|
| https://en.m.wikipedia.org/wiki/Matoke
| cmrdporcupine wrote:
| It took me until my 30s to make the connection that bananas
| cause me intense headaches. I used to love to eat them, but now
| won't touch them.
|
| I think I'm fine with them cooked, but not raw.
|
| I don't know the mechanism, but if you do searches on bananas
| and headaches you will find people prescribing them as a cure
| for headaches, not the other way around.
| btylke wrote:
| It could be a latex allergy. Bananas are one of a few fruits
| that cause latex allergic reactions.
| wileydragonfly wrote:
| Kiwis. Avocado. Watermelon. Etc etc. the list is long.
| cmrdporcupine wrote:
| I have no problems with those, though. I do recognize the
| latex "feeling" and irritation, but avocados and kiwis
| are part of my regular yum-fest
| interludead wrote:
| I'm also curious about banana wine... wonder if it leans more
| toward fresh banana or that overripe, almost fermented taste.
| dan353hehe wrote:
| If I had to guess, it would be that fermenting bananas into
| wine makes them taste like they were fermented.
|
| In all seriousness though, I can't stand overripe bananas.
| Bleah.
| vgrafe wrote:
| I went a couple years ago in coutryside Rwanda, where locals
| brought me to a place where I could have some homemade banana
| wine, or "Urwagwa" (not sure about the spelling!). That place
| was someone's house with a few people hanging out and drinking,
| the wine was served in already-opened glass bottles.
|
| For those curious, it is not very boozy (maybe around 7%-10%
| abv), but very yeasty - to a point where it kinda numbed my
| mouth. For those curious the yeast is the dominant flavor,
| followed by banana. Very earthy taste.
|
| Later on I saw Urwagwa sold in a can at the airport, it was
| very different, no yeast but bitterness instead. I preferred
| the homemade one.
| quijoteuniv wrote:
| The article explains nothing, and has a very suspicious typo. If
| i heat something organic to 370 degrees i do want it to die :D
| interludead wrote:
| Science helping tradition instead of replacing it
| sjmulder wrote:
| The explanation as to why flour yeast and grape wine yeast are
| unsuitable is a bit of a tautology. I know little about yeast.
| Can someone explain why one sort of yeast is not suitable for
| another use? And why is "sorghum, the traditional fermenting
| agent of banana wine" unsuitable or not acceptable to regulators?
| yial wrote:
| Sorghum is acceptable I believe. It's the fifth most produced
| crop in the world. It sounds like what might not have been
| acceptable is using wild yeasts to ferment it.
| dluan wrote:
| It's similar to the malting process. Certain ingredients will
| contain enzymes and other important metabolites that can break
| down complex sugars into smaller simpler sugars that can be
| eaten by yeast (glucose, fructose). You need them to get a
| fermentation started and warmed up.
| stubish wrote:
| Even more confusing: "We mixed the fermenting agent with
| sorghum flour to keep the traditional color and aroma of
| sorghum, the traditional fermenting agent of banana wine"
|
| So they developed a yeast to replace the sorghum as the
| fermenting agent, and then mix sorghum in. What has been
| gained? Does yeast make for a more controlled fermentation
| making regulation easier? Or just easier to industrialize?
|
| I _suspect_ that using sorghum for fermentation really means
| using whatever wild yeast happened to be on the sorghum, and
| the results too variable to regulate for commercial sale or
| export.
| dmurray wrote:
| > I suspect that using sorghum for fermentation really means
| using whatever wild yeast happened to be on the sorghum, and
| the results too variable to regulate for commercial sale or
| export.
|
| Definitely this. Sorghum is not a "fermenting agent": it's
| not an organism that eats sugars and shits out alcohol and
| carbon dioxide (actually, it's pretty much the opposite).
| It's just somewhere wild yeast likes to live.
| jrflowers wrote:
| Different yeasts have different temperature and alcohol
| tolerance. For example a bread yeast may not continue making
| alcohol beyond 5-6%, or another yeast may only be productive in
| a narrow temperature range that's too warm or too cool for a
| given application.
| amonon wrote:
| To add on, different yeasts also vary in their ability to
| metabolize carbohydrates. In general, a wine yeast will be
| less able to metabolize complicated carbohydrates than a beer
| yeast. Beer yeast tends to be more sensitive than wine to
| alcohol levels. More importantly, it's possible Rwanda lacks
| any serious brewer's yeast industry that is suitable. Kveik
| may be able to ferment at both 37C and up to 16% ABV but
| that's definitely an unusual trait in a yeast and I would not
| be surprised if they resulting wine was... funky.
| metalman wrote:
| bannana wine, just does not work well in.english or bannana beer,
| or bannana cider, would be interesting to hear the term or terms
| used localy that might be evocative and perhaps marketable but
| certain words just dont work together..... like english, and
| cuisine, ha ha! it is and will forever be english food. rooooll
| your ooooo's
| s0rce wrote:
| Sorry, native english speaker here, what is wrong with banana
| wine?
| metalman wrote:
| nothing.....if you can make it work.....but in many native
| english markets, it wont, cept perhaps the kiddy booze
| market, where if you mix in enough tuarzine(whatever) and ???
| purple blobs of some goo, it will jump off the shelves but as
| a meal acompanyment, no wait wait, with german desert wines
| going extinct there could be a market for a desert wine
| so......go for it, mang!
| idunnoman1222 wrote:
| Normally, you ferment at lower temperatures because your drink
| will taste disgusting... (there will be terrible byproducts) this
| article has no explanation as to why this traditional drink
| suddenly tastes fine with a high temperature yeast other than
| something about regulators accepting some shit. I imagine that
| traditionally they they didn't add commercial yeast... they just
| opened the top of it and prayed.. and the wild yeast which
| probably where they live Ferments fine at higher temperatures
| however, I had to make this all up in my head because there is no
| fucking information in this entire article and certainly no
| science and I'm amazed it's number three. What the is this shit
| fmbb wrote:
| Normally when you make banana wine?
| jerrysievert wrote:
| I think you need to try some kveik yeast, that might change
| your mind on high temperature fermentation: kveik is a
| Norwegian yeast, somewhat recently (last 25 years) rediscovered
| but brewed with for centuries, and can handle 37oC without the
| byproducts.
| declan_roberts wrote:
| They've been making banana wine from wild yeast presumably for at
| least a 100 years or longer. It sounds like the regulators in
| their country are a PITA and won't get out of the way.
|
| There's a million different strains of yeast but they all do the
| same thing. If you don't add any yeast it will still ferment with
| the wild yeast.
| collyw wrote:
| I was thinking the same. Though wild fermenting works well for
| small batches, I have no idea of it scales. I was guessing this
| is a comercial operation if regulators are involved.
| dluan wrote:
| Regulation is extremely important, and has been part and parcel
| of alcohol and wine production since prehistoric times. Besides
| the health reasons, wine is very easy to cut with synthetic or
| artificial ingredients, which has important economic and health
| consequences - hence the use of government bonding for hundreds
| of years around the world.
|
| But more recently, regulation is vital for setting up
| geographical indicators for production of items that are
| locally unique, e.g. Parmesean, Champagne, and the German
| Reinheitsgebot which are legally protected practices for the
| reasons in the first paragraph. Being able to identify the
| specific strains of yeast in this banana wine is a big part for
| arguing the provenance of it.
| stubish wrote:
| You can't create an export market if you product is variable
| due to your results depending on whatever yeast happened to be
| used that day.
| daurnimator wrote:
| Lambic beers prove you can do that
| ninalanyon wrote:
| So people say. I suspect that as they are made in the same
| buildings over the decades or even centuries that the
| yeasts eventually become part of the local ecology and are
| thus quite stable.
| dluan wrote:
| Bananas are notoriously hard to turn into a cleaner wine, mainly
| because of the fact that most bananas that are not Cavendish have
| a lot of latex and turn into goop. Most of the places where
| banana wine is produced (tropics) ultimately also turn it into
| banana "gin", and there's an incredibly deep and long cultural
| history of its production, e.g. it's tied to British colonialism
| in West Africa funded by liquor revenues, regulation was a hot
| topic of local protests, and drinking bars used to be hotbeds of
| nationalist agitation. When Nkrumah's CPP took over Ghana, they
| legalized homemade wine/liquor as a symbol against the gin
| drinking imperialists (in 1890 a bunch of countries in Brussels
| banned liquor importation to Africa).
|
| The other much easier to produce wine and spirit comes from palm
| sugar (akpeteshie in Ghana, toddy in Indonesia), but the time
| window of when it is fresh and can be consumed is counted in
| hours, so it's not stable enough as an agricultural product to
| sell. Banana wine is an easy way to turn surplus calories into
| surplus cents.
| prmph wrote:
| But fresh palm wine is now bottled for sale in Ghana at least.
| I know because I've bought some in Ghana several times. Not
| sure how they preserve the freshness and prevent further
| fermentation though.
| ginko wrote:
| They could pasteurize it or kill the yeast with sulfites like
| they do with wine.
| skirge wrote:
| what they want to achieve? Biofuels?
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