post centrifuge filtraion

[thornbridgerob]

Currently we centrifuge only to achieve bright beer for packaging, however over time on certain heavily hopped beers I am noticing some degree of haze break out despite some upstream treatment. I am considering some form of post filtration.

My main concern is that I don't want to strip out flavour. I realise there will be some trade off for colloidal stability, but how much?

The options I have are:

- A lenticular
- A superpack https://www.pall.com/main/food-and-b....page?id=52739

Both would have a 6 micron pre filter in place.

Does anyone have experience of either or both? How much flavour stripping could I expect? Would I be able to run my centrifuge faster with the post filtration?

Any help would be much appreciated.

Cheers

Rob

[dick murton]

Why not use a DE filter with post filtration trap to ensure no KG carry over? I would have thought for the volumes you are talking about filtering that this would be a better, albeit more complex solution.

I don't understand why you want to put a 6 micron prefilter in the system. This is liable to block up before the depth filter you are proposing to use. The whole point of these Pall filters is that they are depth filters and are less prone to blockage than surface filters. Yeast is approximately 7 micron diameter, so if particles (not necessarily yeast of course - probably protein) is your problem, then you will do better with a DE filter. And if particle this size are your problem, it suggests your centrifuge is either not suitable for such fine material, or is not set up to work properly.

If you are not already using it, consider using hydrated silica gel for protein stabilisation, which is the most likely source of the haze.

Sent you a PM as well.

[thornbridgerob]

post centrifuge filtration

Hi Dick,

Thanks for the feedback. I have emailed you separately but will also respond here in case any other brewers want to input.

Firstly the 6 micron filter was suggest my the pall representative in order to protect the expensive superpack module. What tends to happen is sporadically a glob of yeast will get past the centrifuge particularly during discharge. I might add this doesn't happen very often but I want to stop this happening.

I appreciate what you are saying about a DE filter. However I have over the last twenty years used both horizontal leaf and plate and frame filters, both of these definitely strip out flavour more than just a centrifuge. I have tasted a beer which was superb after a centrifuge but once it was sent through a plate and frame it literally became 2 dimensional and a different beer all together. Filter manufacturers will always tell you filtration won't take anything away from your beer but it certainly does. I'm really wanting to have my cake and eat it here, a colloidally stable beer but still full of flavour.

I might add I'm also not a fan of the craft trend of tank beer. I think this is for lazy brewers who don't or can't filter their beer and then use it as a way to market their beer as 'natural'. These beers are invariably too yeasty and mask the majority of flavours.

One final point, I am treating up stream as well and I can tell you my regime when you drop by.

Feel free too e-mail me directly rob@thornbridge.co.uk

[adebower]

Hi Rob,
I have been using Pall's supradisc II lenticular as my primary filter for 4 years (K900 module, 8-10 micron) which has given us brilliantly clear beer, but as you mention it does strip aroma and our head retention post filter has suffered.
We commissioned the Alfa Brew 250 last week and while we only have a few runs through it I have noticed a few things about our beer:
Coming off the centrifuge we can get equally brilliant beer without the use of a filter
The aromatics are much more intense and much more in line with how we designed the beers to be coming out of the centrifuge
At discharge a little bit of yeast does come through. I say a little bit because I don't have a way to quantify that amount, but it isn't a slug of yeast. It's more like a momentary flash of beer from the tank pre-filter.
When feeding the centrifuge with heavy load beer at roughly 55 hecto/hour we have seen the outlet turbidity go from 0% to 1%. We did a count on the 1% turbidity beer and it came in at 200,000 cells/ml. I have used the lenticular filter post centrifuge since we're still proving out the functionality. But I can tell you that we're leaning towards doing away with post filtration all together.
I get the sense that the centrifuge is somewhat temperamental much like the horizontal leaf de filter in that it requires a filter/centrifuge operator with a good feel for filtration and a bit of voodoo magic to keep it all working properly. That's just a feeling though.
Good luck.
Adam

[thornbridgerob]

post centrifuge filtration

Hi Adam,

Thanks for your feedback. I will give you a little bit of history of our experience with centrifugation:

When I first started here the beer was relatively bright for all beers coming of the centrifuge: lagers less than 1 EBC and heavily hopped beers less than 2 EBC. The issue was that after a month the heavily hopped beer threw a large amount of sediment. The lagers were completely fine. I consulted a finings company to take a look at the issue and after measuring tannin levels they confirmed it was unreacted polyphenols from late hopping which was causing the issue. I resorted to treating the beer prior to the centrifuge and this improved the colloidal stability of the majority of our beers immensely. However I am still having issues with the extremely heavily hopped beers 80EBU plus. Bags of flavour but still a sediment ( I have attached a photo, this beer was fine for the first few months but after 3 month a sediment appeared)

The other issue is the odd slug of yeast getting through, this is when the centrifuge discharges. The issue with our current centrifuge is that the discharge time has to be set manually. As where more advanced centrifuges will discharge in relation to turbidity and I believe this is where the issue may lie.

So I am really looking for a solution to help me avoid such sediments over time and potentially running my centrifuge faster. I believe that in the US a lot of the more established brewers started centrifuging only, which was fine for local and fresh beer beer however they needed to look at some form of post filtration for export etc.