Methodology
With bottle variation a significant potential issue, it is essentially impracticable to examine different methods between different bottles, unless a large number of bottles is used (impracticable). The method used therefore has been to attempt to examine various aspects within each individual bottle, rather than between bottles. To do this, for each test I have effectively decanted in a single pour, while switching the container/funnel/filter mid-decant (yes, this makes a mess and a small amount of waste, but it seemed the only fair way without affecting the pour). Each test has been slightly different as described below, but in all cases:
- A single bottle is decanted
- Three freshly cleaned and dried decanters are used
- A set of three identical, freshly cleaned and dried glasses are used
- Each decanter is labelled 1-3
- Each glass has a small white sticker marked 1-3 placed on the underside of the base (directly under the stem) so that the writing is not visible from above (for the pedant desirous of precise detail, I placed a first sticker with black scribble on it on the underside, and then the sticker with the number on it on top, the scribble to ensure the number could not be seen through the paper from behind)
- The wine is decanted appropriately for the test into each of the four decanters (as per notes for specific test procedure)
- The glasses are lined up as 1-3, and an identical pour is made from decanters 1-3 into glasses 1-3 respectively
- I leave the room, and my lovely assistant (who thinks I am slightly mad) swaps the positions of the glasses
- I return and place stickers A-C on the top side of the base of each glass
- I smell and taste the wines and make an assessment, making notes against A-C
- Once all assessment is done, I check the underside of the glass to reveal the letter->number mapping
- I placed blank stickers over the visible A-C stickers (in fact a scribble sticker and then another blank one on top)
- I leave the room, and my lovely assistant rolls her eyes and swaps the glass positions again
- I return, and place stickers W-Z on the top side of the base
- I smell and taste the wines and make an assessment, making notes
- Once all assessment is done, I check the underside of the glass to reveal the second letter->number mapping
Using the above method, I have performed several tests over the last few months, as follows:
- (a) Bottle from lying, stood for 15min, opened and decanted immediately; first third through surgical gauze, second third through unbleached coffee filter, then last third through another filter paper
(b) As above, but filter paper first, gauze second, filter paper again third
(c) Bottle stood for 24hrs, gauze, filter paper, filter paper
(d) Bottle stood for 24hrs, unfiltered, filter paper, filter paper
(e) Bottle stood for 24hrs, decanted direct to glasses and single decanter as: unfiltered, gauze, filter, filter(decanter)
Tests (a) and (b) were performed once, (c) and (d) several times each (2,3 respectively) and (e) performed once.
Summary of results
The following observations were made:
- From (a): The bleached filter paper used in (a) will not be used again.
- From (b): There was negligible difference between the initial filter paper vs last filter paper, implying little difference between filtered start and filtered end of bottle.
- From (c),(d): At D+0h, minor perceptive differences were noted in both smell and taste, but were not generally consistent between successive tests; no method was either consistently good or consistently bad. It is noted that since the number of tests performed is small, variation is likely to outweigh deteermination of any small method bias which may be present, but there is clearly no significant bias.
- From (c),(d): At D+4h, the minor perceptive differences seem to have disappeared; very occaisionally one of the glasses might seem very slightly weaker than the others but if so it was borderline detectable at this stage.
- From (e): At d+0h, the wine decanted through filter paper into glass seemed to be very slightly flatter/affected on both nose and taste when compared with the unfiltered and gauze-filtered; however, after 1hr in glass no difference was noted between the unfiltered and filtered.
Conclusions
- If filter paper is to be used, then I am much less concerned about standing up time than previously.
- Filter paper also yields the clearest result, as well as getting the maximum from the bottle.
- There *may* be a slight effect to the nose/taste as a consequence of using (unbleached) filter paper, but if so it is very small and was only noticeable when a small amount of wine is passed through the filter (a glass) and not when a larger amount is filtered (a third of a bottle). This effect seems to disappear after 1-2hr in the glass.
- Test (e) needs repetition to check this result for consistency. If consistency is shown, it could be interesting to try "seasoning" the filter paper, perhaps by passing a glass of water through it first.