Home Made Flow Hoods

[Bizier]

Hey all,

I have been thinking about constructing a flow hood for a while, as my second-floor Sydney inner-west rental residence is just not the place to play with yeast.

I am wondering if many Aussies have constructed their own on the cheap? If you have, I'd love to see pics.

I was reading up on this the other night and found this online, and realised that I actually had this edition sitting on my shelf, and had not paid attention to that article as I had bought it as a set. Anyway, the author talks about using a cheap air purifier caulked onto a tub.

The most attractive air purifiers I have seen are the Honeywell ones with replaceable HEPA filters, but these are still about $150 and expensive to ship from the US. My tentative idea is to get something like this and place a bank of computer fans behind it to create sufficient positive pressure. See attached diagram.

I would appreciate any input from anyone that know something about aerodynamics. I have this, which I thought was a great source, but I would like to know if it could be done with smaller sized filters.

Cheers
Dan

 

[pdilley]

I built laminar flow walls overseas, not just a hood an entire wall

The only way to get airflow was to use squirrel cage fans. Closed box systems are old tech. The idea is the closest point to the wall is the cleanest air flow and it blows contaminants back towards you and the room so you order your petri dishes, innoculum, etc. accordingly.

These things:

Each one of my Hepa filters were the size of table tops

Kind of like what these guys are in front of:

I got them from a scientific online auction house, a whole palette load.

And used this book for ideas on how to build the units:

Your smaller filter idea is admirable but as you blow in clean air you will stir up contaminants and swish them all around an enclosure which is why the world moved on to laminar flow walls and benches. Constant clean air pressure blowing contaminants downstream.


A bit over kill for beer though no?


Cheers,
Brewer Pete

 

[Bizier]

A bit over kill for beer though no?

Perhaps, but I would like to be able to have somewhere clean to pour things. I would like to be able to propagate yeast with any degree of cell increase (e.g. from a commercial bottle) and trust in the that my results will be relatively pure. And now I have seen people propagating mycelium, I am keen to try my hand for shits and giggles.

Also, I will add that my idea is to keep a spray bottle of isopropyl alcohol or similar inside the container to kill what is in there, and use positive pressure to dry the alcohol and expel fumes.

 

[pdilley]

Yes but then you can not flame sterilise with flamables in the area, so you'll need a bacticinerator to ssterilise your loops as you work

The human body is a huge vector of contamination itself. All those cells sluffed off and in general is a host to many little organisms. All the flow hoods and walls bring you is more success with minimising losses. You still get work done even as low tech as a warm oven and working under it's heat plume that pushes floating particles away from you working on the open door area.

But if you are bit with the mad scientist bug, give it all a go for kicks.


Cheers,
Brewer Pete

 

[Wolfy]

Perhaps, but I would like to be able to have somewhere clean to pour things.

Have you had problems with foreign infections when working with yeast samples in the past?

 

[Bizier]

Have you had problems with foreign infections when working with yeast samples in the past?

Reusing yeast, yes. I know there are many potential reasons for this, so I have switched to a glass carboy and aim to top crop using the blowoff method before I have taken my first gravity sample (or now that I think of it, that is a decent method of taking a gravity sample by lowering the intake). My main reason is that I would like to be able to reliably go from a handful of cells to a commercial sized pitch cleanly. Perhaps one day I want to consider an open fermentation brewery.

 

[Bizier]

I have nearly finished my glove-box-with-HEPA.

I took the centre out of the lid of a 100L storage tub, and also one of the side panels and glued transparent vinyl sheet across the gap.

Currently the filter is a Volta Ultima U5005 type one from ebay with 3 x 140mm computer fans behind it. While it does create a positive pressure in the chamber, it is quite soft. I am thinking of adding more juice behind the filter.

The idea is that I will cut into the side sheet so that it acts more or less like the old fly straps at a butcher (yes I am aware that microbes are bigger than flies).

I will try to get a post of some of my cutting configurations.

I would also like to know if anyone can tell me if it is safe to spray a HEPA filter with IPA (the isopropyl one). As I understand it, the filter is basically tight woven fibreglass. I can't see why IPA should harm it.

I also have not made a pre-filter.

 

[Bizier]

Here are the options I am considering for cutting in my arm holes.

Despite the fact I was tempted to draw nipples on it, I am thinking number 5 looks good.

 

[Banshee]

Geez getting a bit carried away eh?
I buy a Wyeast smack pack. Get it started draw out some yeast sluury with a needle and syringe then culture on some dishes. I do ten at a time. Wyeast $14 and 10 dishes $7.50. total of $21.50 for ten plates plus the pack to make a starter. About $2 a culture. When I want to brew scrape off the yeast into some malt solution and away I go. Clean yeast every time. With the amount of yeast you scrape off the plate I would be very suprised if something over rides it and takes control.

If on the other hand I wanted to have a bank of yeast and regenerate from 1 sample I would think about the air. I did do an experiment an left a dish open to the air for an hour or so and the growth of wild stuff was unbelieveable. Plus you need a microscope to make sure the yeast you want to continue culturing stays clean. You can only tell with magnification and training.

It's all fun though.

 

[Wolfy]

Option 5, that way you get to fondle the boobies each time you use it.
But seriously, cut out the full semi-circles and tape the top to make a flap, then cover the side and flaps with a larger piece of the vinyl and they will act as a vent meaning you don't need to cut to the sides or top of the box.

Given that AFIK most contamination risk comes from falling dust, is the lid covered with one solid piece of vinyl or (as per the pictures) are they strips with spaces between them?
Either the side or the top of the container gives you a nice clear viewing window, but I'm not sure on the theory of doing both?

Looking at your box/design, it has me curious as to if the fans and filter are actually required at all.
Clean and disinfect the inside of the box, attach the lid, add samples, and spray the inside with sanitizer, wait 24 hours, stick your gloved hands through the holes, sanitize again, and the risk of infection from anything inside the box should be negligible. The last few sets of slants I made were from isolated single cell yeast colonies grown on agar, and I did those on a clean/sanitised TV table in the dining room, so if that works for me, I'm sure that whatever design you end up with will go well to increase your chance of success (or more likely minimize the chance of failure by infection).

 

[funkydiscochicken]

like this?

 

[Wisey]

haha, nice

 

[drsmurto]

Stick a pair of these in - Gloves

That's a glovebox MacGyver would be proud of! :icon_cheers:

 

[raven19]

:icon_offtopic: I am picturing Homer dropping a radioactive sample inside the booth at the power plant!

Back On Topic - I reckon taping Smurt's glove suggestion would be the way to go for sure.

Edit:

 

[Bizier]

Any info on using IPA on a HEPA filter?

 

[Bizier]

cut out the full semi-circles and tape the top to make a flap, then cover the side and flaps with a larger piece of the vinyl and they will act as a vent meaning you don't need to cut to the sides or top of the box.

I am unsure exactly what you mean. Perhaps my construction is not clearly illustrated.
I removed the centre of the lid and glued a sheet of vinyl over this, and did the same with one side. I have not yet added the arm holes to the side vinyl panel.
There is no gasket sealing the lid, I figure dust can't get in unless it is sucked in somehow.

Given that AFIK most contamination risk comes from falling dust, is the lid covered with one solid piece of vinyl or (as per the pictures) are they strips with spaces between them?
Either the side or the top of the container gives you a nice clear viewing window, but I'm not sure on the theory of doing both?

My idea was simply that vinyl is better to poke your arms through than polypropylene. The top is definitely for viewing, but also for me to breathe creepily on while I watch the yeast and their daughters get busy.
FWIW if you need to glue polypropylene HOT GLUE is the business. I hadn't used it for years and did not think highly of it, here is a definite time and place.

 

[Wolfy]

I am unsure exactly what you mean. Perhaps my construction is not clearly illustrated.
I removed the centre of the lid and glued a sheet of vinyl over this, and did the same with one side. I have not yet added the arm holes to the side vinyl panel.

My suggestion was for how I'd imagine you create the arm-holes, using #5 in your picture as a guide.

 

[seravitae]

Beizer, sorry mate that will not be laminar flow and front face convection will cause issues. Also, you need a large amount of airflow, that little fan won't cut it. You need a big blower fan (usually called a squirrel cage fan), which also requires a very large HEPA filter.

The fan should be placed in a seperate section at the back to which the hepa filter rests across the whole back surface, so that the fan air pressurises the back of the filter and flows out laminarly into (and out of) the hood...

 

[Bizier]

Thanks Sera, yeah it is def not a laminar flow hood, just a glove box. I guess I will have to test to see if the filter enhances or detracts.

Thanks Wolfy, I like the idea of a second flap over the hand holes, if that is what you were explaining.

I guess that the proof is all in the pudding. Worst case scenario, I fill it with CDs or something

ED: This has made me aware of the soft cleanrooms that you can purchase. I am thinking that I will def knock one of these up when I have enough space. I can imagine that these would have to be good if you were trying to do yeast work in an old building or large open space.

 

[Wolfy]

Thanks Wolfy, I like the idea of a second flap over the hand holes, if that is what you were explaining.

Seemed logical to me (when I posted it at 1am).