Stainless Steel vs Glass Fibre Filter for Spirits?

[tgif]

Hi All,

Looking for some recommendations regarding filtering. I'm currently using the 4 nozzle Enolmaster to bottle multiple flavors of gin (no sugar) and possibly whisky in the future.

1. What are the advantages and disadvantages of using stainless steel vs glass fibre filters?

2. Am I able to add pre-filter cartridges beforehand without affecting speed?

3. What filter materials are recommended for pre-filtering?

 

Thanks.

[adamOVD]

Call TCW equipment. They sell them in all varieties and are very knowledgeable and helpful. If using fiber you will want a dedicated gin cartridge.

[MichaelAtTCW]

Stainless steel filters are—in my humble opinion—a waste of money. I think people buy them based on an incorrect assumption. Namely, that they'll last longer or be more reusable. The thinking goes something like:

1. Plastic is disposable. It has a finite lifespan, and most plastics must eventually be discarded
2. Stainless steel is reusable, and most stainless steel implements last indefinitely
3. Filters made of plastic (or glass) components must eventually be discarded
4. Therefore…
5. Filters made of stainless must last indefinitely!

It ain't necessarily so. Filters must be discarded because they eventually get plugged up with tiny particles. Cleaning/backflushing can help up to a point, but eventually there is no amount of regeneration that can bring the filter back. The crud is baked in to the filter pores. This happens regardless of whether the filter is made of plastic or stainless steel.

Stainless steel is more difficult material to make into the kind of porous material that makes for effective filtration. Consequently, stainless steel filters are generally more expensive, less efficient, and tend to clog more quickly than filters made of glass, polypropylene, etc. Stainless steel filters are great for applications where the filtrate is too hot, cold, or aggressive for normal filter media types, but I don't think they make sense in most beverage applications. They cost more, and the perceived benefits are illusory.

So what does work well for spirits? Pleated glass fiber cartridges (like the Graver GFC cartridges we carry) are great for spirits. Because glass fiber media carries a slight ionic charge, it is more effective at picking up haze-forming colloids and the like. Pleated polypropylene (like the QMC cartridges we carry) is the all-purpose standard. It is inert, so no charge, but very effective at general solids removal.

WRT your second question about pre-filtering affecting speed, it shouldn't. Every filter has different nominal flow rates, which will be affected by all sorts of upstream factors. The rule of thumb I count on is that you will see about 3-5 GPM of flow rate for every 10" of filter. So if you are using a 30" filter, you should see a maximum potential flow rate of 9-15 GPM. If you are using two, three, or more 30" filters in series that doesn't change anything. If one of the filters clogs you will see a decrease in flow rate, of course.