# Potato Peel Oxygen Generator



## Lyrebird_Cycles (7/6/17)

Following on from ADRs excellent experimentation: 

I foolishly left my oxygen cylinder at the winery so I needed to make up something simple and cheap.

Materials and methods:



h2o2_1

One strip of potato peel, one length of silicone tubing, two cable ties, 30% peroxide and a piece of stainless rod (as a weight).

Sanitise everything except the peroxide and the potato peel by boiling.

Seal off one end of silcone tubing, add 1 ml peroxide and strip of poatato peel, seal other end, spray with sanitiser.



h2o2_2

Throw into wort at yeast pitch.

The idea is that the catalase in the potato peel catalyses the breakdown of the peroxide to water and oxygen, the oxygen then permeates through the silcone tubing into the wort.

1ml x 0.3 g/ml H2O2 = 0.3g. 16/34 x 0.3 = 140mg, 140mg / 15 litres = 9.4 mg/l O2.

The permeability of this tubing is enough for the O<sub>2</sub> to dissipate well inside 24 hours.

Just to check that my calculations were correct I made up another one and placed it into a glass of water. The peroxide breakdown seemed to be complete in about 15 minutes (though I guess this will be very dependent on the potato peel). After an hour or so the diffusion of the oxygen through the silicone became very obvious. In wort which isn't already saturated with oxygen and where yeast is actively scavenging, I expect it would dissolve directly into the wort.



h2o2_3

In the spirit of experimentation I split the wort in two and only threw the oxygenator in one (after pitching). A slight complication is that I added oleic acid to the yeast during the bulk up.

Hey mods: the old software did subscripts and superscripts in the top panel. I can't find them in the new software. Many downvotes from me.


----------



## peteru (8/6/17)

Neato! 

I'm going to have to have a go at this! Extremely simple and cost effective.


----------



## Lyrebird_Cycles (8/6/17)

The silicone tubing I used is a special high permeability tubing, not generally available: I had about a thousand metres made to my specs by a company in Denmark some years ago, almost all of it got used for the project for which it was ordered.

The closest I can find off the shelf is item no 310 0810 from Gecko Optical. You'll need to use a slightly greater length, say 15mm per litre of wort.


----------



## Adr_0 (8/6/17)

That's awesome... my biggest issue now is getting experimental batches out of the way as the results can be hit and miss and take some of the enjoyment/reward out of the beer. As useful and satisfying as it is, information doesn't taste and nice as a well brewed batch of beer.

Funnily enough I was about to recommend those guys as I've found a number of uses for their silicone tubing. I originally bought some 10mm OD x 6mm ID to use for penetrations into my mash tun and kettle lids, but have also used it for sealing around false bottoms and distribution trays - great stuff. Now I've found another use...


----------



## Lyrebird_Cycles (8/6/17)

The permeability is proportional to surface area / wall thickness, you'll find the tubing you have has less than half the permeability of the tubing I recommended.


----------



## Matplat (8/6/17)

Is it just those dimensions that permeability is proportional to, or is it also to do with however the silicone is actually manufactured?

I have some cheap chinese silicone that probably has 1mm wall thickness... Ultimately I'l experiment in water, and see if it look like yours after an hour.


----------



## Adr_0 (8/6/17)

Lyrebird_Cycles said:


> The permeability is proportional to surface area / wall thickness, you'll find the tubing you have has less than half the permeability of the tubing I recommended.


Good pickup - i'll grab some of that.


----------



## Lyrebird_Cycles (8/6/17)

Matplat said:


> Is it just those dimensions that permeability is proportional to, or is it also to do with however the silicone is actually manufactured?



It's a function of the dimensions mentioned, the void space within the polymer and the solubility of oxygen in the polymer. There are small variations between silicones with different types of cure and average MW. The biggest difference we found was in how quickly the permeability dropped over time, which we assumed was due to fouling, but that was in an application where the silicone was immersed in wine for weeks at a time. The Danish manufacturer's product stayed stable for many weeks, some trial tubing we bought off the shelf fouled very quickly. In red wine you could detect the fouling because the tubing changed colour.

BTW I'm working on something that will be simpler, cheaper and won't involve chemicals but it's under wraps for now as it's related to something on which I'm applying for IP protection and I don't want to risk the IP application.


----------



## n87 (8/6/17)

I can see a market for glow stick style, single use oxy sticks.

boil, crack in half, throw in wort... oxygenation sorted


----------



## Lyrebird_Cycles (8/6/17)

That would be really easy to make. Seal the peroxide in a glass ampoule, coat the outside with manganese dioxide, seal in a silicone tube.

To use, crack the glass ampoule.

If you want to try this, a cheap source of manganese dioxide is a standard zinc carbon battery. You can buy sealable ampoules from a lab supply, the trick is to seal the end without heating the contents. If you hold the ampoule in the middle you'll learn very quickly (or burn your fingers if you are too slow).


----------



## n87 (8/6/17)

If you can make it so it ends up being ~$1 a hit, I think there will be a fair takup of the people who dont have the dosh to throw ~$200 down on a O2 setup.
Sell in a 20 pack.


----------



## Adr_0 (8/6/17)

A bit of dried potato peel powder in there...


----------



## Lyrebird_Cycles (8/6/17)

That's the organic option.


----------



## Lyrebird_Cycles (8/6/17)

n87 said:


> If you can make it so it ends up being ~$1 a hit, I think there will be a fair takup of the people who dont have the dosh to throw ~$200 down on a O2 setup.
> Sell in a 20 pack.



The silicone tubing alone is about $3.

The as yet unrevealed alternative is a bit of hardware that you could make yourself for $10 and will run indefinitely without needing any replenishment. Cost of use will be about 0.1c per 25 litre batch. As I said it's related to something else I'm working on so I can't reveal it yet.


----------



## n87 (8/6/17)




----------



## Lyrebird_Cycles (8/6/17)

To be clear, I have no intention of marketing this. The device for which I'm applying for IP protection is for a different purpose in a different market.

Part of it is made of platinated titanium so it's in a different price league as well.


----------



## Lionman (8/6/17)

n87 said:


> If you can make it so it ends up being ~$1 a hit, I think there will be a fair takup of the people who dont have the dosh to throw ~$200 down on a O2 setup.
> Sell in a 20 pack.



My O2 setup cost under 100 and should last for 100 batches before I need a new bottle.

What happens to the silicone tubes when they go into landfill?


----------



## Radshoes (8/6/17)

Lionman said:


> My O2 setup cost under 100 and should last for 100 batches before I need a new bottle.
> 
> What happens to the silicone tubes when they go into landfill?



Not sure, leave anote for your grandkids grandkids, and when they work out time travel they might come back and tell us?


----------



## Adr_0 (8/6/17)

Lionman said:


> My O2 setup cost under 100 and should last for 100 batches before I need a new bottle.
> 
> What happens to the silicone tubes when they go into landfill?


Siloxanes, which then turn to sand in the power station generators?


----------



## malt junkie (8/6/17)

Lyrebird_Cycles said:


> The silicone tubing alone is about $3.
> 
> The as yet unrevealed alternative is a bit of hardware that you could make yourself for $10 and will run indefinitely without needing any replenishment. Cost of use will be about 0.1c per 25 litre batch. As I said it's related to something else I'm working on so I can't reveal it yet.


So if this piece of hardware were to continually make O2, it would need to be removed 24-48 hrs after pitch?


----------



## Lyrebird_Cycles (8/6/17)

No. Further details in a few weeks.


----------



## OneEye (8/6/17)

What if you put a diffusion stone on one end of the hose?


----------



## Lyrebird_Cycles (8/6/17)

For what purpose?


----------



## OneEye (8/6/17)

Instead of requiring the special high permeability hose you just have a normal one with the stone on the end


----------



## malt junkie (8/6/17)

moosebeer said:


> Instead of requiring the special high permeability hose you just have a normal one with the stone on the end


the permeable hose only exchanges gases, your stone will allow wort in to mix with your potato peel.


----------



## Lyrebird_Cycles (8/6/17)

You beat me to it. Since the potato peel can't be sterilised by normal means the possibility of wort ingress makes the whole thing an infection risk.

It also makes calculating gas egress over a given time scale more difficult as you are dealing with d'Arcy's law for porosity rather than Fick's Law for permeability.


----------



## Lionman (8/6/17)

Lyrebird_Cycles said:


> You beat me to it. Since the potato peel can't be sterilised by normal means the possibility of wort ingress makes the whole thing an infection risk.
> 
> It also makes calculating gas egress over a given time scale more difficult as you are dealing with d'Arcy's law for porosity rather than Fick's Law for permeability.



I wish I knew what you know. Always a fountain of awesome info. Please keep posting!


----------



## peteru (9/6/17)

However, a diffusion stone attached to a reservoir of H2O2 and some sacrificial yeast (as a source of catalase) might be less risky in terms of infection. Especially if you could balance the contraption in such a manner that the stone would be at the top and filed with slightly pressurised O2.

I've got heaps on my plate for the next 6-8 weeks to tinker, so I'm quite happy to sit this one out and see what invention LC comes up with once he files the paperwork for "the other project."


----------



## OneEye (9/6/17)

Ah I didn't realise the stone would allow wort in. Oh well, worth a thought. As said before, keep posting. This info is awesome!


----------



## wynnum1 (9/6/17)

Magnesium oxide is a catalyst for hydrogen peroxide breakdown for oxygen have you looked at using vitamin supplement as a cheap source what they use for horses is probably the cheapest.


----------



## Lyrebird_Cycles (9/6/17)

I think you mean manganese dioxide which I already mentioned. To my knowledge magnesium oxide is a poor catalyst.


----------



## Lyrebird_Cycles (9/6/17)

Gravity readings (in oP)

Day____Control____Potato

Tues____13.5______13.5
Wed____12.8______12.9
Thur_____9.2_______9.7
Fri______6.1_______5.6
Sat
Sun

Edited to correct values in table, I did these by refractometer read the wrong column in the conversion spreadsheet.


----------



## Adr_0 (9/6/17)

Try Alt + 0176 for the °P


----------



## Lyrebird_Cycles (10/6/17)

Gravity readings (in oP)

Day____Control____Potato

Tues____13.5______13.5
Wed____12.8______12.9
Thur_____9.2_______9.7
Fri______6.1_______5.6
Sat_____4.3_______2.6
Sun

After 4 days "potato" is close to expected FG , control is lagging.


----------



## Jack of all biers (10/6/17)

Lyrebird_Cycles said:


> In the spirit of experimentation I split the wort in two and only threw the oxygenator in one (after pitching). A slight complication is that I added oleic acid to the yeast during the bulk up.



Interesting results so far. What was done with the control? Was it aerated at all (given your O2 bottle was elsewhere)?


----------



## Lyrebird_Cycles (10/6/17)

In case that's not clear, both "potato" and control had oleic acid added to the yeast during yeast prep. No other assistance was given.

If it tails off I'll move it on to the lees of the "potato" ferment. I don't really need to do sensory on the two ferments, I already know I prefer oxygenated ferments to non-oxygenated. This was about whether my cowboy oxygenation method would work.


----------



## Lyrebird_Cycles (11/6/17)

Gravity readings (in oP)

Day____Control____Potato

Tues____13.5______13.5
Wed____12.8______12.9
Thur_____9.2_______9.7
Fri______6.1_______5.6
Sat_____4.3_______2.6
Sun____3.8_______2.6

End of experiment, I'll now move the control over the "potato" yeast to finish it off.


----------



## n87 (11/6/17)

Interesting that the control took off stronger, but the potato finished strong.
I guess the potato yeast were too busy getting jiggy with it to eat... then they found that they were starving.


----------



## Lyrebird_Cycles (11/6/17)

I suspect my split of the yeast bulk up was a bit uneven and more yeast went into the control.


----------



## malt junkie (11/6/17)

The most striking differences are over the last 3 days the potato sample really powered on, and this is where you really need good healthy yeast for the clean up phase. Something I noticed with a few brews over the years those that struggled to get down those last few points really didn't clean up well. Nice little experiment, looking forward to your other method.

Mike


----------



## Lyrebird_Cycles (11/6/17)

I've decided to lodge only a preliminary patent application for the work to which the "other method" is related while I get some more testing done.

I won't be publicising anything related to it until I decide whether a full patent is worthwhile, likely just before the year's grace from the preliminary expires which will be June 2018.

Sorry for the tease.


----------



## malt junkie (11/6/17)

LC I think the one thing brewing teaches is patience, I'll probably be enjoying the next RIS I brew in 2019, and I know it'll be worth the wait.

MJ


----------



## Adr_0 (11/6/17)

Lyrebird_Cycles said:


> I've decided to lodge only a preliminary patent application for the work to which the "other method" is related while I get some more testing done.
> 
> I won't be publicising anything related to it until I decide whether a full patent is worthwhile, likely just before the year's grace from the preliminary expires which will be June 2018.
> 
> Sorry for the tease.


Not a worry at all - all the best with the testing and development!

Thanks very much for the detail on the method and the results - very interesting and it has certainly planted a seed in my mind.


----------



## wynnum1 (12/6/17)

The problem i see with hydrogen peroxide is obtaining the hydrogen peroxide and storage if you do not have a use for concentrated or access then its going to be expensive and possibly dangerous and if using diluted expensive , could sodium percarbonate be used to create the hydrogen peroxide solution for the potato peel.


----------



## Lyrebird_Cycles (18/6/17)

Yes, but it will make judging the level more difficult as you'll have to know the exact peroxide level of your percarbonate: the commercially available stuff is generally about 30% peroxide I believe.


----------



## dr K (1/7/17)

Manganese Dioxide (that black powdery stuff in old style batteries) as noted is an excellent catalyst for oxygen generation from H2O2.
Adding some Manganese Dioxide to a Sodium Percarbonate solution produces a pretty fast reaction!! You could do it in a pressure container, say a 9 litre cornie with convenient disconnects or even a PET bottle with one of those carbonation lids. Straight out to your oxygen stone....10g of Sodium Percarbonate will produce over a litre of oxygen.


----------

