diff --git a/BrewBar/BrewBarApp.swift b/BrewBar/BrewBarApp.swift
index 0499a28..22c96b7 100644
--- a/BrewBar/BrewBarApp.swift
+++ b/BrewBar/BrewBarApp.swift
@@ -169,10 +169,15 @@ class AppDelegate: NSObject, NSApplicationDelegate {
         return url
     }
 
+    /// Serial: brew commands run strictly one after another. Concurrent brew
+    /// processes could each summon their own sudo password dialog (and their
+    /// log output interleaved); queueing them prevents both.
+    static let brewQueue = DispatchQueue(label: "fr.socheleau.BrewBar.brew")
+
     /// askpassMessage customizes the sudo dialog ("...password to <message>.");
     /// defaults to naming the brew command.
     func runBrew(_ command: String, askpassMessage: String? = nil, completion: @escaping (String) -> Void = { _ in }) {
-        DispatchQueue.global().async {
+        Self.brewQueue.async {
             let brew = self.resolveBrewPath()
             let cleaned = command.replacingOccurrences(of: "brew ", with: "")
             let arguments = [brew] + cleaned.split(separator: " ").map(String.init)