---
title: Barritt’s B reagent
description: "Barritt’s B reagent consists of 40% potassium hydroxide (KOH). It is used with Barritt’s A reagent (alpha-naphthol dissolved in ethanol) to detect the presence of [2,3-butanediol](https://vumicro.com/docs/voges-proskauer-test/) (so-called \"neutral fermentation products\") produced from glucose in [MRVP broth](https://vumicro.com/docs/mrvp-broth/). After inoculating MRVP broth…"
url: "https://vumicro.com/docs/barritts-b-reagent/"
updated: "2022-06-17"
category: Reference Library / Reagents, Chemicals, Stains
---

# Barritt’s B reagent

Barritt’s B reagent consists of 40% potassium hydroxide (KOH). It is used with Barritt’s A reagent (alpha-naphthol dissolved in ethanol) to detect the presence of [2,3-butanediol](https://vumicro.com/docs/voges-proskauer-test/) (so-called "neutral fermentation products") produced from glucose in [MRVP broth](https://vumicro.com/docs/mrvp-broth/).

After inoculating MRVP broth and incubating overnight, five drops of each reagent are added to the culture. Barritt’s A should be added first.  This is followed by addition of five drips of Barritt's B. Development of a red color indicates the presence of 2,3-butanediol.

---

## VUMIE is the flight simulator of microbiology labs.

  [Learn more about VUMIE](https://vumicro.com/)