diff -r a167ee979cac -r 641540dc6ef2 src/EditProductTab1.cpp
--- a/src/EditProductTab1.cpp	Tue May 17 14:37:26 2022 +0200
+++ b/src/EditProductTab1.cpp	Tue May 17 16:57:48 2022 +0200
@@ -306,6 +306,8 @@
 	ui->brew_logLabel->hide();
 	ui->brew_logButton->hide();
     }
+    ui->brew_ackLabel->hide();
+    ui->brew_ackButton->hide();
     if (product->stage < PROD_STAGE_BREW) {
 	ui->brew_startButton1->show();
         ui->brew_startButton2->show();
@@ -342,6 +344,12 @@
 	    ui->brew_endDate->setReadOnly(false);
 	    ui->brew_endTime->setButtonSymbols(QAbstractSpinBox::UpDownArrows);
             ui->brew_endTime->show();
+	    if (product->brew_date_end.isValid() && product->brew_date_start.isValid() &&
+		(product->brew_date_start.msecsTo(product->brew_date_end) > 7200000)) {
+		/* The start and end dates are valid, and the end is more then two hours after the start. */
+		ui->brew_ackLabel->show();
+		ui->brew_ackButton->show();
+	    }
 	} else {
 	    ui->brew_endButton1->hide();
             ui->brew_startLabel2->hide();