beta-Sitosterol in spirits

[nabtastic]

Hey everybody,

I want to give a big shout out to BDAS in Lexington, KY for their great lab work (I'm purely a customer and in no other way affiliated).

Recently got results back regarding beta-sitosterol in spirits. I was wondering if anyone else has had issues with high levels of sterols or any other precipitation in the bottled? I know that I can filter down to 0.5 micron to solve it but I'd prefer to limit the amount of sterols coming across to the finished spirits because so much flavor is lost.

I have a strong feeling that it is coming from our choice of cooperage but I'm not 100% and waiting for new barrels to arrive and fully mature a product isn't ideal given that I'd be waiting in excess of a year. I believe it the cooperage is the culprit because no sterols precipitate out in our white spirits - even though it's lower proof and I have left in the freezer to facilitate precipitation.

Is it possible that the wood used in the barrels themselves have not been seasoned long enough? Any other options there? I still have several months before the barrels from a different source are ready for testing..

Thoughts?

Thanks,

NAB

[mendodistilling]

Ask the barrel company

[nabtastic]

I appreciate the response but that didn't really help. Black Swan said they age for less than 6 months (which I assume means they don't intentionally age) and Kelvin said they had never heard of anybody having issues with sitosterol (we don't use Kelvin yet but I have used in the past without known issues).

I make agricole (fresh pressed) cane and to my understanding sterols and waxes are inherently present in the cane but it's unlikely they survive rectification/distillation. This is reinforced by the fact that we have had zero issues with unaged spirits. So I'm still confused how exactly it becomes a problem - length of aging, non-chill filtering, heat, proof, etc?

[jeffw]

What is the taste of beta sisterol? I have noticed a slight funky taste (sorry, hard to describe the taste, slightly eucalyptus like) in some of my black swan barrels up to about 14 months (30 gallon barrel), but then it seems to fade away.

[nabtastic]

Jeffw - I can't say that I have a specific taste to attribute to it. We sent samples to a lab in Lexington, KY to ensure that the "floaties" / precipitants were actually beta sitosterol. I will say that I've noticed a pine flavor (probably what you taste as eucalyptus) with a creosote and sawdust aromas (plenty of positive notes too but that's not what this thread is about). Sitosterol is essentially wood sugars but I don't know a specific flavor profile associated with it.

NAB

[patrick260z]

Just making sure your comparing apples to oranges... The sitosterol is across multiple barreled lots? The unaged spirit is from the same sitosterol lots in barrel? Only asking because I've seen wax flakes come across at the very end of a tails run happen, which logic and the nature of partial boiling pressures would dictate that some tiny degree of those waxy compounds are present in all parts of the distillation. Maybe this problem lot was distilled at too low of a proof? Allowing more of those compounds to come across? Or perhaps a bad heads cut? The heads of the next run can pull alot of higher alcohols and waxes stuck to the walls of your still.

With whiskey barrels, coopers don't really season at all if they can help it. They kiln dry, this also allows them to use more of the soft sap wood. These two facts are why our american charred barrels are sub-200/bbl and the wineries are paying over 500/bbl, too BTW. But the kiln drying process is industry standard, to my understanding. I don't think the soft sap wood is the sitosterol source, because then one would think that the problem would be more prevalent.

[nabtastic]

Patrick260z - that's an excellent question (and info). I wasn't working for the company when these particular batches were distilled so I can't answer with absolute certainty. Given that our canes tend to be waxy I could definitely see the issues coming through in distillation lending me to believe (without further lab analyses) that cleaning between runs would be mandatory. Normally I wait until I see scaling but if it keeps the wax out .. certainly not the worst solution

[patrick260z]

Other then there being waxy bits in the distillate, are there any other negatives? Could you do some sort of loose filtration?

[nabtastic]

Flavor of the distillate is on point and I've not noticed any visible waxes ever. That being said, some of our cane has considerably higher levels of wax on it and it's not uncommon to collect wax from filtered pressed juice in distilleries and sugar mfc plants. I've filtered with cellulose to 3 microns and still had issues and it seems to be completely removed with cellulose filtration at 0.5 micron. However, the complexity is lost a bit doing that as well (seems "flatter" if you'll allow the term). I do not presently have a filter between 1-3 microns (not sure why the range is so wide) and 0.5 microns.

[patrick260z]

Have you compared the filtered to unfiltered blindly after a month or so? From my experience with wine, differences in flavors between filtered and unfiltered only existed shortly after filtration. After about a month, when compared blindly, were near- indistinguishable. Additionally, some filtration methods can introduce dissolved oxygen into the solution. Which can also affect flavor. What type of filtration system are you using?