user4748: I drink kombucha, a fermented and very slightly alcoholic tea, in order to ease recurring gastrointestinal distress. Although I use this drink as a tool, is it considered a breach of the fifth precept? 

user289: Buddhist morality, as a rule of thumb, has to do with how such actions affect your ability to practice (i.e. can you still meditate), and does it cause suffering in yourself or others, as opposed to morality being based in compliance with the demands of a supernatural being.
So, on those grounds, this amount of alcohol is not problematic. It won't make you behave in a way that makes you break the rest of the precepts. 
As for how institutional Buddhism handled alcohol, it varied, I'll link because they say it better than I can summarize.
As for how much Kombucha you'd need to drink to get smashed and risk breaking the rest of the precepts...you'll start puking and farting before you get drunk on Kombuch, this guy tried it. ...almost a gallon of noxious fermented tea just to break a blood alcohol level of 0.01

user471: The purpose of that precept is to prevent loss of heedfulness through intoxication.
If your reason to drink tea of some kind with very little alcohol in it, is for medicinal purposes, and if it does not cause the loss of heedfulness through intoxication, then there is no violation of the precept in my opinion.

4748: <p>I drink kombucha, a fermented and very slightly alcoholic tea, in order to ease recurring gastrointestinal distress. Although I use this drink as a tool, is it considered a breach of the fifth precept? </p>
 289: <p>Buddhist morality, as a rule of thumb, has to do with how such actions affect your ability to practice (i.e. can you still meditate), and does it cause suffering in yourself or others, as opposed to morality being based in compliance with the demands of a supernatural being.</p>

<p>So, on those grounds, this amount of alcohol is not problematic. It won't make you behave in a way that makes you break the rest of the precepts. </p>

<p>As for how <a href="https://link.springer.com/referenceworkentry/10.1007%2F978-94-024-0852-2_150" rel="nofollow noreferrer">institutional Buddhism handled alcohol, it varied, I'll link because they say it better than I can summarize</a>.</p>

<p>As for how much Kombucha you'd need to drink to get smashed and risk breaking the rest of the precepts...you'll <a href="https://www.vice.com/en_us/article/mvx484/i-tried-to-get-drunk-on-kombucha-511" rel="nofollow noreferrer">start puking and farting before you get drunk on Kombuch, this guy tried it</a>. <code>...almost a gallon of noxious fermented tea just to break a blood alcohol level of 0.01</code></p>
 471: <p>The purpose of that precept is to prevent loss of heedfulness through intoxication.</p>

<p>If your reason to drink tea of some kind with very little alcohol in it, is for medicinal purposes, and if it does not cause the loss of heedfulness through intoxication, then there is no violation of the precept in my opinion.</p>
