Prepping A Barrel That's Been Stored Dry

The small barrel mentioned above was bone-dry for months. I submerged it in water and let it soak for about 5 days, drained it and filled with water. Within a couple days the exterior was dry and its been leak free for about two weeks.

Is there a good way to sanitize this barrel without stripping too much of its character?
Would Starsan work? How much, how long?
I’ve read recommendations for sodium metabisulfite (2 tsp/gal) plus citric acid (1 tsp/gal).
Should I be less concerned with stripping its character, and re-season with bourbon or whatever as needed?

Any and all input is appreciated……

 

Appreciate the input.

My paraphrased takeaways from the Sanitizing section of the Milk the Funk Wiki on stored barrels:

‘Brettanomyces begins to die at around 98.6°F (37°C) on surfaces. Complete thermal death occurs at 122°F (50°C) in wine.

‘The experimental designs of two studies (2011 & 2013) were criticized by two later studies (2015 & 2018). The earlier studies said steam is not an effective way to kill all Brett in oak barrels, the later studies reported that steam is effective.
The 2015 study proposed that the most effective and preferred method is to heat the inside of the oak barrel to at least 140°F (60°C) for 20 minutes with hot water* or steam. It was demonstrated as effective way to kill Brett growing as deep as 8 mm within the wood of 3-year-old barrels infected with Brett. (Note: Note that this might not be hot enough to kill other heat-tolerant microbes; however, these heat-tolerant species tend not to be able to survive in beer.)

‘The 2018 study confirmed the 2015 results and reported that as little as 12 minutes of steam was enough.
Of inoculated barrels, oak barrels with heavy toast levels tended to have higher populations of Brett.
French barrels required 12 minutes and the American oak barrels required only 9 minutes at 131°F (55°C) to eliminate all Brett from even the deepest points into the oak.
Hot water* was also reported by the same research group to effectively eliminate Brett from oak barrels, although it took longer; 158°F (70°C) for 30 minutes or 176°F (80°C) for 20 minutes.
*Hot water tends to remove more of the barrel character than steam.

‘It has been reported that extensive heating can destroy desirable oak flavor compounds. Degradation of these compounds requires temperatures between 248°F (120°C) and 365°F (185°C) for 1 to 6 hours, so significant degradation of desirable oak flavor compounds is not expected to occur with 12 to 20 minutes of 131°F (55°C) to 140°F (60°C) of steam pasteurization.’


What I ended up doing (5-liter barrel):
1) Filled the barrel with boiling water and let it rest for 30 minutes. This was done mainly to raise the temperature of the barrel and make the second effort more effective at holding the temperature.
2) Emptied the water, boiled it again, refilled the barrel and bunged it tight as practical.

Using a non-contact thermometer at the end of the second 30-minute rest, the outside of the heads registered 125°F and the outside of the staves were 116°F. A probe thermometer inserted about 3” into the barrel through the bung hole registered 176°F. The discharge from the valve was a relatively consistent 168°F.
The first draining had noticeable bourbon barrel character. The second draining not so much.

I’ll probably do that two-step process one more time and insulate the barrel to see if I can get the outsides up to 158°+(F) for 30 minutes.
Thinking about adding some spirits when done (bourbon, rum [Myers Dark?], not sure).
I read elsewhere that one can use one of those flexible, extended butane lighters to add some new toast/char. I’m not convinced it would be effective but might give it a go.