I'm still around but with the unseasonably warm weather (
70's in February!) have been busy outside working on my aging house and property. I've been working off a 30' extension ladder all day and am tuckered out plus it has started raining so... tonight I will sit, drink some coffee and post.
I experimented with many different filtering methods/variations and for ethanol based extractions I've settled on this for enhanced oil reduction;
- Once the flavor extraction is complete I -currently- use a nylon nut bag for separating the tobacco from solvent. The nylon bag lets more particles through than would a coffee filter but absorbs less extract and is considerably stronger, better suited for squeezing. Once separated, I seal the extract and place it in the freezer. I've also been eyeing this; Amazon.com: VonShef Professional Stainless Steel Mash Potato Ricer Masher/ Fruit Press With Black Soft Touch Handles: Kitchen & Dining
- After sitting in the freezer (-10F) for a couple of days, I filter the congealed muck that drops out of solution using a coffee filter, a canning funnel and a clean canning jar. I filter the cold extract -inside- the freezer and 100ml generally takes around 15 minutes. I'm careful not to pour any more congealed muck into the filter than is necessary.
- *Once freeze filtering is complete I reduce the extract by around 70%. I do this at room temperature using a fan to blow air across the top of the open container(s). Using 1/2 pint canning jars, 100ml of extract reduces down to 30ml in about 6-8 hours. When using a wide shallow ceramic or pyrex container (like a small soup or custard bowl) the same reduction takes half the time but is more difficult to gauge. This winter I used a small fan forced electric heater to provide warm, dry air flow, it's actually a bit quicker. In the past I used a convection (air circulating) oven set <150F and the reduction was quite rapid, took just minutes once the extract reached temperature. Perhaps a little too fast considering I ruined a couple of extracts by accidentally reducing them till bone dry...
- *Once its been reduced I seal the extract and let it sit, at room temperature, undisturbed, for several days. If present, any oil that dropped out of solution during (because of) reduction will slowly coalesce into a skim or form globules.
- *Finally, after sitting for a few days allowing oil to coalesce, I place the sealed extract back in the freezer for an hour or two. Once cold, and while still in the freezer, I filter it through a 5.5cm 1 micron glass filter. Cold coalesced oils stick to the filter (and filter holder) tenaciously. I then re-seal the filtered extract and allow it to reach room temperature.
- If I'm going to leave it as an alcohol based extract I simply bottle it. If I'm going to transfer the flavor into PG or VG I do that first and then bottle it.
By waiting to filter the extract until
after the reduction I'm able to remove more oil. I "think" the reason for this is, after flavor extraction, our solvent contains dissolved tobacco oils locked up in solution. There isn't anything we can do for a PG or VG based extraction but using ethanol provides us with options. With ethanol, freeze filtering catches any oil and other muck that precipitates out due to the freezing temperature but some dissolved oil remains locked up in solution. When we reduce (
evaporate) the ethanol by 70% any oil locked up in that 70% is left behind in the now condensed extract. The 30% ethanol we didn't evaporate off is saturated and unable to hold the additional oil. Unable to hold it in solution (
dissolved) the additional oil now exists in a free state and will slowly coalesce forming a skim or globules. By chilling the extract (
and excess coalesced oil) before filtering, the oil's viscosity changes, it becomes thicker clinging to the filter better while the ethanol remains highly fluid. Since I'm using a 5.5cm filter I lose very little of the reduced extract to absorption but unfortunately the extract I do lose is highly concentrated, that's the tradeoff for enhanced oil reduction.
My last fifteen extractions were all performed at lower temperatures for longer durations. My goal is to keep the processing temperature well below 150F to preserve flavor. I personally like the results some of these experiments yielded but not all. The last batch was processed at ~140F for 72 hours and produced very promising results. Within that batch were two of the best cigar extractions to date, a Tatiana Vanilla and Acid Blondie.