Centrifuge and Filteration

[Dheeraj]

Looking to procure a centrifuge, but before I do, have a few doubts which I need clarity on.
1. Currently using plate and frame filter (filter press), so will the switch to centrifuge eliminate the usage of filter press completely?
2. Should the filter press still be kept as a back up?
3. Will the centrifuge help reduce filtration losses and increase overall yield?
4. Can centrifuge be used after whirlpool to minimize hot trub loss?

[dick murton]

Re 1 – will it eliminate filtration? This depends very much on what standard of clarity and shelf life you are looking for. First of all, what sort of filter press are you using? If a KG or other filter aid press, then you will probably not reduce the residual yeast and bacterial count by as much as a fine sheet filter. A centrifuge will remove most of the yeast, but very rarely if ever, as much as a filter, especially if using a “sterilising” grade filter (say 0.4 micron absolute) as a final stage. A centrifuge will also not remove as much fine, mainly proteinaceous material which could form chill haze and so you are likely to have a shorter shelf life due to haze. So, particularly bearing in mind India is somewhat hotter generally than say the UK, I would suggest that if you want what is often termed “starbright” beer, with a typical haze of 0.8 ebc or less, then a centrifuge on its own will not suffice.
Having said that, if you are producing dark ales and stouts only, which I very much doubt, then I have brewed / packaged a few beers where centrifugation only was used for clarification, followed by in can or bottle pasteurisation, or flash pasteurisation for keg. It was never sold unpasteurised.
When I reviewed cross flow filter operations, the system with CF forming part of one of the systems (Pall/Westfalia) worked really well on dirty beer ex CCT, but the advantage over the Norit system without a CF was nothing like as great when filtering well sedimented (and normally isinglass fined) beer.
Re 2 & 3. What the centrifuge will do is allow you to increase your volume through a filter press before it has to be turned around (washed off or backflushed according to design, sterilised etc. prior to a new filtration run). For example, one brewery I worked at increased the typical filter run volume 5 to 6 fold by installing a high speed centrifuge – which was perhaps more than most people would experience, but it was a huge increase because we were able reduce the bodyfeed KG dose rate so much.
If you put the CF between FV and CCT, it will reduce the amount of bottoms produced hugely, the slurry ex CF containing far less entrained beer. Secondly, because of increased filter run lengths, you lose less beer on filtration due to fewer turnarounds, spend less on filter powder, and lose less time pre volume produced turning the filter around.

I would suggest that if your beer is dirty and you are getting short filter runs, then look at improving the CCT process so you get clear (unfiltered) beer presented to the filter, before you start mucking about with centrifuges.
Re 4 – personally I wouldn’t bother – a lot of expense for very little gain. A properly designed and operated WP will produce very bright wort, and minimal hot break should be carried over. The cold break won’t have formed at that point, so won’t be removed. If your wort in FV is dirty, then look at sorting out you WP design and operation first.

Finally, if you do decide to install a centrifuge, make sure it is suitable for beer and you know what oxygen pickup levels it should be capable of achieving. There are loads of centrifuges out there. Not all are suitable for beer production. And you need to make sure you can supply suitable quality gas and water supplies, and have a dedicated soundproof room – the CF manufacturers will advise.

[UnFermentable]

Dick makes a lot of great points here.

If you can, connect with Narayan at Geist in Bangalore and ask him about his Andritz centrifuge he owns. I think Vidya is still the Brewer over there and she definitely knows her stuff. Perhaps you can arrange a visit to check out a modern beer centrifuge in operation.

Centrifuges are great tools, but they must be operated correctly and maintained properly.