I'm trying to get to the bottom of a problem which has me stumped. If I brew a light beer such as a wheat beer and bottle condition it then all is well. If I brew a dark beer such as an oatmeal stout then after two weeks of bottle conditioning all is well but if it's left for a longer period of time then it over carbonates. Even if I refrigerate it before opening it will gush up after the cap is removed and loose about 2/3 of the contents. The remaining beer tastes ok so I'm convinced that it isn't an infection. All my equipment and bottles are well sanitised with Star San.
The malt bill for one batch which over carbonated was:
4Kg of pale malt
0.2Kg of Crystal Malt
0.2Kg of Chocolate Malt
0.1 Kg of Black Malt
0.5Kg of Malted Oats
The mash temperature was 68C (154F) for 90 minutes then a 60 minute boil followed by cooling down to around 20C (70F) through a plate chiller. The yeast used was White Labs WLP028 Edinburgh Ale. This was in the primary fermenter for 7 days then transferred to the secondary fermenter for 14 days. Both primary and secondary fermentation were conducted in a temperature controlled cabinet at 19.5C (67F). The OG was 1.053. Gravity after primary was 1.017 and after secondary it was steady at 1.016. I had 18 litres to bottle so I used 70g of sugar made into a syrup into the fermenter to give a carbornation of 1.8.
After two weeks of bottle conditioning at room temperature I opened a bottle and all was well however a few weeks later it was gushing when opened. I've tried WLP007 English Ale yeast and 4 weeks in the secondary fermenter but neither solved the issue.
Any suggestions?
The malt bill for one batch which over carbonated was:
4Kg of pale malt
0.2Kg of Crystal Malt
0.2Kg of Chocolate Malt
0.1 Kg of Black Malt
0.5Kg of Malted Oats
The mash temperature was 68C (154F) for 90 minutes then a 60 minute boil followed by cooling down to around 20C (70F) through a plate chiller. The yeast used was White Labs WLP028 Edinburgh Ale. This was in the primary fermenter for 7 days then transferred to the secondary fermenter for 14 days. Both primary and secondary fermentation were conducted in a temperature controlled cabinet at 19.5C (67F). The OG was 1.053. Gravity after primary was 1.017 and after secondary it was steady at 1.016. I had 18 litres to bottle so I used 70g of sugar made into a syrup into the fermenter to give a carbornation of 1.8.
After two weeks of bottle conditioning at room temperature I opened a bottle and all was well however a few weeks later it was gushing when opened. I've tried WLP007 English Ale yeast and 4 weeks in the secondary fermenter but neither solved the issue.
Any suggestions?