Millipore "sterile" Filters

[NRB]

I purchased a Millipore 'sterile' filter and 2 micron SS stone on Saturday for aerating my wort prior to pitching my yeast. Unbeknownst to me, I managed to pitch my yeast without airstone aeration.

The wort trickles in from my CFWC so this at least adds some aeration, but I bought the filter/stone hoping for a better result than gained via "fast spoon whizzing" It would seem the filter either needs a huge pressure for air to get through it, or mine's blocked from the factory. They're apparently desgined for use with fluids.

I can't get air to pass through it, so the 30mins it sat in my fermenter whilst the wort was filling was useless. Now my yeast have taken more than 24 hours to get any semblance of activity... I decided to aerate without the filter not more than 30mins ago (24hrs post brew) just to see if lack of aeration is the culprit.

Anyone else have similar problems with these filters?

 

[Darren]

NRB, Millipore are possibly the biggest filter company in the world. I doubt there is a problem with their filters (used in Good Manufacturing Processes where humans are injected). What are you using to push the air through the filter? An old aquarium pump won't push the air through. It is entirely possible that you haven't waited long enough for the air to come all the way along the lines . Not sure of the type you have but if has been wet, it will be a lot harder to push air through.
cheers Darren

 

[NRB]

Darren, I'm using an aquarium pump, yes. I guess I need something else; what do you guys recommend.

It's not wet as far as I can tell, but I can't rule out sanitiser running back into the filter at some stage whilst I was setting it all up.

 

[Darren]

Darren, I'm using an aquarium pump, yes. I guess I need something else; what do you guys recommend.

It's not wet as far as I can tell, but I can't rule out sanitiser running back into the filter at some stage whilst I was setting it all up.

[post="87238"][/post]​

If it got wet that could be your problem. You probably have to get a new aquarium pump with high output or bottled oxygen. Chances are you don't need anything at all. If you are making 20 litre or so batches you should be able to airate, by shaking at pitching and at about 12 hr after pitching. Alternatively, make a big starter. I suspect the reason people seem to think they need to airate is because big breweries do it. Breweries make 1000 litres + at a time. It is no suprise that they cannot make a starter to get that going without air.
Darren

 

[Borret]

The pump may just be struggling with the airstone too and the filter is the straw that breaks the camel's back. I used to use a bronze sintered stone which was more porous and then switched to a tighter ss one. The ss one needs heaps more pressure, especially when at the bottom of the ferm. My aquarium pump couldn't move any air when at the bottom. Try the setup in a tall glass bottle with water and compare the air output with the diffuser at the bottom and then when you lift it to various heights. The deeper it is the higher pressure you need. Give it a go and see what you find. If you can simulate your fermentor depth then even better.
I'd say it's a combination of the filter and diffuser as I doubt the filter has a fault. Mediacal level quality assurance would have eliminated that.
Consequently I don't use mine anymore for simplicity and sanitiation fears and as darren said if your starter is big enough and you airate through a turbid drop into fermentor you should still have no attenuation probs.
I will probably still use it for big beers though.

Borret

Edit. do you have the pump going when you drop it in the ferm or turn it on afterwards? This can also make a big difference as it has to push wort back through the stone.

 

[pint of lager]

I use a milipore filter, ss stone and aquarium pump. The pump has dual outputs that get paralleled up with an adapter.

This has just enough pressure to push air through the ss stone.

Make sure you have no leaks. Do a practice run on a bucket of plain water. The slightest airleak will stop the system working. The adapter had a screw adjustment for pressure, this leaked. By nipping the end of this screw off, it could be wound home fully so the thread didn't leak, but allowed full airflow.

I find that the filters block if they get one drop of water in them. They work ok for that day's brew, then are unuseable for the next brewday.

 

[Darren]

Small air compressor could do the job. The sort you plug into th car lighter to pump up your tyres. Not sure if they spit oil though

 

[pint of lager]

Darren, I think you are correct, they will probably spit oil. You could put the output in a glass of water, leave it run for an hour, then check to see if it flavours the water.

 

[Borret]

Small air compressor could do the job. The sort you plug into th car lighter to pump up your tyres. Not sure if they spit oil though

[post="87279"][/post]​

A diaphram compressor won't spit , a piston one may. I used one once or twice no probs

Borret

 

[NRB]

Thanks for the advice. I had it running prior to immersion and the pump is good enough to provide aeration when the stone is at the base of the fermenter WITHOUT the filter inline. I might look at getting a new fandangled multi-port aquarium pump from eBay and feed all outputs into a single line.

I have found that the filter was indeed wet - I used a syringe to continually blast air through the filter which seems to have dried it out somewhat, to what extent is uncertain. I'll find out next brewday I guess.

The good news is that following the aeration (sans filter) the yeast have finally taken off and my first porter is bubbling away beautifully.

 

[Murray]

You would be better off buying a Millipore aervent filter, which is designed for sterile air filtration.