Thirsty Boy
ICB - tight shorts and poor attitude. **** yeah!
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This follows on a little from a discussion in a thread started by Katie - about a traditional African beer made using bananas.
A little research revealed that the beer she was talking about is called Mbege and it is a traditional product of the Tanzania / Kilamanjaro region of Africa. It is made from bananas and unmalted finger millet, and bittered with a tree bark. The traditional beer is acid fermented primarily around the bananas and then the millet is added shortly before consumption (the night before ish). As with most traditional beers it is drunk fresh (basically out of the fermenter) and is cloudy - the yeast and starch haze making up a significant part of it's nutritional value.
This got me to thinking about enzymes - this beer, like all other beers, obviously included an amount of grain starch being converted to sugars by enzymes..... but where were the enzymes coming from?? The grain being used was unmalted millet after all. The answer was of course -- from the bananas.
Bananas (and plantains) when they are unripe, are very rich in starch - as they ripen, the starches are converted to sugars. So in there - are enzymes that do the same sort of job as the amylase enzymes in malted grain. It turns out that bananas convert their starches primarily with phosphorylases that crack starches into glucose and fructose (so basically invert sugar) at an optimal temperature of about 30C - BUT - that later in the ripening phase, both Alpha and Beta amylase levels increase and reach a maximum as the banana attains complete ripeness. This means that not only are there starch converting enzymes in bananas ... they are the same enzymes that we manipulate when we make a beer from malted grains.
So --- All that meshes in with my mini quest to find a way to brew beers from gluten free grains, without having to malt the grains before using them (which is just a part of the larger quest to learn about enzymes and starches and how they work) I decided to make a modified version of an Mbege - a clearer more "modern" version that still used the unmalted gluten free grains as a starch source, and converted the starch to sugar entirely with the enzymes contained in the bananas. Can I make the starch convert? Can I make a palatable beer? Why don't I have a life and better things to do with my time?
Here's what I did.
Mbege Recipe: (ingredients etc are as planned - OG, efficiency etc are reverse engineered from the results)
Batch size - 2.2L
Expected OG - 1.043
IBU - 16
Mash Efficiency - 63%
Ingredients
Millet Flour - 200g
Sorghum flour - 100g
Miaze Flour - 100g
Banana Flesh - approximately 260g consisting of 4 x medium bananas. 1 very very ripe (black), 2 quit ripe (moderate brown spotting) and one quite unripe with about a 50/50 mix between green and yellow colour
Hallertau Hersbrucker Hop pellets - 3g for about 16IBU (90 min)
Method
I was absolutely unsure if this would work, so I decided to mash the hell out of it, with the focus being on preserving the enzymes as much as possible.
*Flours were mashed in with 1.5L of cold tap water - the very ripe and unripe bananas were blended into the mash (bamix)
*A glass aquarium heater was inserted in the mash set to 32C - mash raised to approx 30 and maintained. Mash rested at 30C for 5-6hours\
*Aquarium heater removed and mash cooled and diluted with 750ml more tap water. Mash rested at ambient for the balance of 24hrs.
The previous steps were to allow thorough hydration of the starches and to give the banana phosphorylases (optimum temp 30) time to act on any available starch in the mash.
The next steps are basically a version of the gluten free "reverse" decoction method - the gluten free grain needing to be raised to 80C plus to gelatinise its starch, but the enzymes being preserved in the decanted liquid.
*The mash has "settled" during its overnight rest - decanted off as much clear liquid from the top of the mash as I could (about 900ml)
*One of the mostly ripe bananas was blended into the remaining "thick" portion, the other blended into the enzyme liquid.
*The thick portion was brought slowly to the boil and boiled for nearly three hours - it formed a quite thick paste.
*The paste was allowed to cool down to 40C and the enzyme liquid was mixed back in with a little more cold water. This formed a thin batter at about 32-35C. This was covered and left to mash overnight.
Once again, the overnight rest was to give the phosphorylases a chance to work on the now gelatinised grain starches
*After the overnight rest, the whole mash pot was placed in a very slow oven with a temp probe inserted into the middle of mash.
*Over 5-6 hours with occasional stirring the mash temperature ramped up to 55 -- and then I got bored and impatient.
*Mash removed from oven and placed on stove top.
*Heat mash to 62 with constant stirring - allow to rest 35mins
*Temp dropped to 50 - increase heat to 67 and rest for 30mins
*Temp dropped to 58 - increase heat slowly to 75
*Transfer mash to mash filter bag (made of T'shirt material) and add 750ml boiling water. Hang overnight to drain.
*Next morning add a further 750ml "bach sparge" to the filter bag (stirring well etc etc) and hang to drain while I am at work
*After 13hrs at work (long day.. sigh) add final batch sparge amount (about 1.5L) and fall into bed.
This extended lautering process is nothing really to do with teh experiment and more to do with my stubborn refusal to chuck away the GF flours I bought and go out and buy some proper grain.... I will learn to brew reasonably with flour. Then I will never bother to do it again!!
*Next morning with a bit of a squeeze of the bag I had collected 4 or so litres of moderately cloudy wort
*Wort brought to the boil and tossed in 3g of hersbrucker hops
*Boiled for just short of 2 hours until target volume of 2.2L was reached
*Strained hot wort through rough filter funnel to get rid of hops and put back into rinsed boil pot. Brought back to boil for a second (sanitation) and then lid on and into sink full of cold water for a cool
*Wort (break and all) transfered into a 4L demijohn for fermentation and pitched with a 150ml starter of Wyeast 1308
*8-12hrs lag time and wort is currently approaching high krausen.
So - did it work?? Yes it did. I don't know if the beer will taste any damn good. But the banana enzymes (or something anyway) certainly converted some starches into sugar. Rather better than I thought they would actually.
According to the nutritional information I found on the internet (so it must be true) - 260g of banana would contain about 30g of pre-existing sugar. That much sugar is enough to give 2.2L of liquid a gravity of 1.005 ... and my 2.2L of liquid ended up at a gravity of 1.043. So the balance of the sugar must have come from starch conversion.
Conclusions -- Well, you can do it basically. You can, if you are bloody minded enough, make a beer with unmalted grains and convert their starches with enzymes from nothing else but ripe bananas. If the beer is actually drinkable .. I might even try to scale it up to a full batch and frighten some people with it at case swaps or something. God help the poor comp judges
cheers
Thirsty
A little research revealed that the beer she was talking about is called Mbege and it is a traditional product of the Tanzania / Kilamanjaro region of Africa. It is made from bananas and unmalted finger millet, and bittered with a tree bark. The traditional beer is acid fermented primarily around the bananas and then the millet is added shortly before consumption (the night before ish). As with most traditional beers it is drunk fresh (basically out of the fermenter) and is cloudy - the yeast and starch haze making up a significant part of it's nutritional value.
This got me to thinking about enzymes - this beer, like all other beers, obviously included an amount of grain starch being converted to sugars by enzymes..... but where were the enzymes coming from?? The grain being used was unmalted millet after all. The answer was of course -- from the bananas.
Bananas (and plantains) when they are unripe, are very rich in starch - as they ripen, the starches are converted to sugars. So in there - are enzymes that do the same sort of job as the amylase enzymes in malted grain. It turns out that bananas convert their starches primarily with phosphorylases that crack starches into glucose and fructose (so basically invert sugar) at an optimal temperature of about 30C - BUT - that later in the ripening phase, both Alpha and Beta amylase levels increase and reach a maximum as the banana attains complete ripeness. This means that not only are there starch converting enzymes in bananas ... they are the same enzymes that we manipulate when we make a beer from malted grains.
So --- All that meshes in with my mini quest to find a way to brew beers from gluten free grains, without having to malt the grains before using them (which is just a part of the larger quest to learn about enzymes and starches and how they work) I decided to make a modified version of an Mbege - a clearer more "modern" version that still used the unmalted gluten free grains as a starch source, and converted the starch to sugar entirely with the enzymes contained in the bananas. Can I make the starch convert? Can I make a palatable beer? Why don't I have a life and better things to do with my time?
Here's what I did.
Mbege Recipe: (ingredients etc are as planned - OG, efficiency etc are reverse engineered from the results)
Batch size - 2.2L
Expected OG - 1.043
IBU - 16
Mash Efficiency - 63%
Ingredients
Millet Flour - 200g
Sorghum flour - 100g
Miaze Flour - 100g
Banana Flesh - approximately 260g consisting of 4 x medium bananas. 1 very very ripe (black), 2 quit ripe (moderate brown spotting) and one quite unripe with about a 50/50 mix between green and yellow colour
Hallertau Hersbrucker Hop pellets - 3g for about 16IBU (90 min)
Method
I was absolutely unsure if this would work, so I decided to mash the hell out of it, with the focus being on preserving the enzymes as much as possible.
*Flours were mashed in with 1.5L of cold tap water - the very ripe and unripe bananas were blended into the mash (bamix)
*A glass aquarium heater was inserted in the mash set to 32C - mash raised to approx 30 and maintained. Mash rested at 30C for 5-6hours\
*Aquarium heater removed and mash cooled and diluted with 750ml more tap water. Mash rested at ambient for the balance of 24hrs.
The previous steps were to allow thorough hydration of the starches and to give the banana phosphorylases (optimum temp 30) time to act on any available starch in the mash.
The next steps are basically a version of the gluten free "reverse" decoction method - the gluten free grain needing to be raised to 80C plus to gelatinise its starch, but the enzymes being preserved in the decanted liquid.
*The mash has "settled" during its overnight rest - decanted off as much clear liquid from the top of the mash as I could (about 900ml)
*One of the mostly ripe bananas was blended into the remaining "thick" portion, the other blended into the enzyme liquid.
*The thick portion was brought slowly to the boil and boiled for nearly three hours - it formed a quite thick paste.
*The paste was allowed to cool down to 40C and the enzyme liquid was mixed back in with a little more cold water. This formed a thin batter at about 32-35C. This was covered and left to mash overnight.
Once again, the overnight rest was to give the phosphorylases a chance to work on the now gelatinised grain starches
*After the overnight rest, the whole mash pot was placed in a very slow oven with a temp probe inserted into the middle of mash.
*Over 5-6 hours with occasional stirring the mash temperature ramped up to 55 -- and then I got bored and impatient.
*Mash removed from oven and placed on stove top.
*Heat mash to 62 with constant stirring - allow to rest 35mins
*Temp dropped to 50 - increase heat to 67 and rest for 30mins
*Temp dropped to 58 - increase heat slowly to 75
*Transfer mash to mash filter bag (made of T'shirt material) and add 750ml boiling water. Hang overnight to drain.
*Next morning add a further 750ml "bach sparge" to the filter bag (stirring well etc etc) and hang to drain while I am at work
*After 13hrs at work (long day.. sigh) add final batch sparge amount (about 1.5L) and fall into bed.
This extended lautering process is nothing really to do with teh experiment and more to do with my stubborn refusal to chuck away the GF flours I bought and go out and buy some proper grain.... I will learn to brew reasonably with flour. Then I will never bother to do it again!!
*Next morning with a bit of a squeeze of the bag I had collected 4 or so litres of moderately cloudy wort
*Wort brought to the boil and tossed in 3g of hersbrucker hops
*Boiled for just short of 2 hours until target volume of 2.2L was reached
*Strained hot wort through rough filter funnel to get rid of hops and put back into rinsed boil pot. Brought back to boil for a second (sanitation) and then lid on and into sink full of cold water for a cool
*Wort (break and all) transfered into a 4L demijohn for fermentation and pitched with a 150ml starter of Wyeast 1308
*8-12hrs lag time and wort is currently approaching high krausen.
So - did it work?? Yes it did. I don't know if the beer will taste any damn good. But the banana enzymes (or something anyway) certainly converted some starches into sugar. Rather better than I thought they would actually.
According to the nutritional information I found on the internet (so it must be true) - 260g of banana would contain about 30g of pre-existing sugar. That much sugar is enough to give 2.2L of liquid a gravity of 1.005 ... and my 2.2L of liquid ended up at a gravity of 1.043. So the balance of the sugar must have come from starch conversion.
Conclusions -- Well, you can do it basically. You can, if you are bloody minded enough, make a beer with unmalted grains and convert their starches with enzymes from nothing else but ripe bananas. If the beer is actually drinkable .. I might even try to scale it up to a full batch and frighten some people with it at case swaps or something. God help the poor comp judges
cheers
Thirsty