Oak Preparation Experiment

I have been attempting to recreate the Bourbon character achieved by Goose Island in their Bourbon County Brand Stout through their use of recently emptied, second use, bourbon barrels, by seasoning, toasting, and then charring my own White Oak prior to soaking it in barrel strength spirit.  My most recent attempt at doing this (which was the first attempt that I used something close to enough oak) turned out to have a very rich oaky character but missed the mark quite a bit on the oak character of bourbon (or BCBS).  I believe my treatment of the oak is the reason for this failure.  This post will be used to document some experimentation with different oak treatments

In my previous batches I have toasted my oak in the oven and then charred the oak with a propane burner or torch (see a post on my previous oak preparation here).  In retrospect, after tasting the beer made with the oak, I suspect that these levels of toast and char (or some combination of each) was too high as my whiskey has a flavor profile much more slanted to caramel than vanilla (while bourbon is more vanilla than caramel to my palate).  I'd like to test different levels of toast and char and how these impact the flavor of the spirit.  Unfortunately, I find my notes are also a little too vague and that the process used was a bit cavalier so that replication of exactly what I did isn't possible.  I need to find a way to do some testing in a more repeatable way as part of this experiment as well

Some thoughts:

• Barrel makers toast their barrels in front of an open flame for relatively short amounts of time (I understand something on the order of 30 minutes although this seems to be treated as a somewhat closely guarded trade secret).  I would expect this would lead to a varying degrees of toast within the oak and the exposure of spirit to oak cooked at different levels.  The oven doesn't seem like a great tool to replicate this as the oak most likely toasts more slowly at oven temperatures and then you have to leave it heated longer that creates a more even toast in the internal parts of the oak.  Based on this, I've decided to try to toast the oak via a cast iron pan.  This will apply greater toast to the outside of the oak than the inside and, although the temperature levels aren't as measurable as they are in the oven, we can get a repeatable set of results using the various heat levels of the range
• For charring the oak I have been thinking mostly about the look of the charred piece of wood (getting an 'alligator char' for example).  Thinking about it in terms of the number of quick passes of the flame over the wood seems like a better way to get varying degrees of char and to do it in a more repeatable way

Based on this, I have decided to test how oak prepared with 4 different levels of toasting and 3 different levels of charring does in recreating the bourbon oak character in a spirit

• Variable #1:
• Low Toast (toasted for 5 min per side on the range's low temperature)

• Low +1 Toast (toasted for 5 min per side on 1/3 of the way between Low and Medium)

• Low +2 Toast (toasted for 5 min per side on 2/3 of the way between Low and Medium)

• Med Toast (on the rage's medium temperature)

• Variable #2:
• 1 Pass Flame (1 pass per side)

• 2 Pass Flame (2nd pass over all sides)

• 3 Pass Flame (3rd pass over all sides - effect similar to alligator char)

Experiment Notes:

• 7/9/22
• Cut white oak that seasoned outside for a year and a half into 1 inch x 1 inch x 1.5 inch pieces.  This size was chosen to roughly match the ratio of oak to spirit used in a bourbon barrel given that I'll be use 16 oz mason jars to do this aging
• Toasted 3 pieces of wood at each of the toast levels specified above
• Charred the 3 pieces of each of the 4 toasting samples at the various levels of char from variable 2
• Mixed the 95% ABV Everclear with Spring Water to get a 62% spirit and put this in my 12 mason jars (used 10.5 oz Everclear to 5.5 oz Spring Water for this)

• Added one piece of oak to each of the jars and labled the lids

• Moved these to my attic where they will experience nightly temperature swings which will speed up the aging process
• 7/23/22 - Color extraction has varied quite a bit after the first two weeks of aging:
• Low Toast:

Left to Right:  1 Pass, 2 Pass, and 3 Pass Char

• Low +1 Toast:

Left to Right:  1 Pass, 2 Pass, and 3 Pass Char

• Low +2 Toast:

Left to Right:  1 Pass, 2 Pass, and 3 Pass Char

• Medium Toast:

Left to Right:  1 Pass, 2 Pass, and 3 Pass Char

• 1 Pass Char:

Left to Right:  Low, Low+1, Low+2, and Medium

• 9/3/22 - It has been almost 2 months since I started aging this oak in my hot attic.  Color seems to be pretty much done changing over the last month.  So, I'm thinking it is time for a taste and aroma evaluation:
• I have decided to do the evaluation against a barrel strength bourbon and selected the Maker's Mark Cask Strength Bourbon for this purpose.  This is a 56% ABV product while my spirit is 62-63%.  These strength differences will impact the Taste test so I will water down my sample slightly to try to match the makers mark (1/8 tsp of spring water to 1 tsp of my whiskey should do the trick)
• I am going to evaluate the color, aroma, and flavor of my samples with this test.  The goal here will be to find which oak treatment produces a flavor most like a real bourbon (which comes down to the right balance between vanilla and caramel flavors).  I'm going to use a school letter grading scheme for these.  I will consider a lack of vanilla to be a defect and an excessively high degree of caramel, roast, or smoke to be a larger defect in my scoring.
• This is going to be a bit of an endurance test to drink 56% spirit but hopefully I'll be able to assess these with just tiny sips
• Here is my scoring:

• To summarize the findings:
• The Low+2 Toast and 3 Pass Flame sample creates a flavor profile that is very similar to the makers mark (thus, an A-).  It has a very good balance between vanilla and caramel flavors which are just slightly less bold than the real thing.  I think this sample is close enough to allow me to proceed with aging more oak using this preparation method.  My assessment of the next Bourbon County Stout clone with this Oak Preparation Method will tell me if I need to expend more energy improving the A- to an A with more experiments
• The medium toast produced quite a bit of acrid and charred flavors in all cases.  Toasting to a point where the wood is smoking is a mistake to be avoided.  These were all a fair bit darker than the real thing as well.
• The low toast didn't produce much flavor at all regardless of the level of char.  I believe this confirms the importance of the toast to getting the good flavors.
• Low toast +1 produced some good flavors but they were less bold than the higher toast.  Toast levels are definitely a variable to be considered carefully
• The Low+2 Toast samples with more char were better than the 1 pass flame ones in color, aroma, and flavor so char is clearly also a very critical component to the whiskey
• 2 months in the attic seemed to be enough time for the flavors to be extracted nicely at this scale.  I will do another sample in a month or two to see if more time does any good