A slightly different approach this time. I’m making the starter just 24 hours before I need it, pitching yeast at 15℃ and keeping the stir plate in a cool room instead of regular room temperature. This is due to a number of inputs;
Ideal fermentation temperature for S-189 is stated as 9-15℃ so I don’t want to run the risk of introducing off flavours by having the starter spinning away at 25℃, which would be the case were I to leave it in the kitchen as usual.
I’ve also noted that some yeast tends to become subdued after too much time on the stir plate, so I reckon that 12-18 hours stirring and another 10-8 fermenting should be enough time for the yeast to work up an appetite. We’ll see how this goes.
As per Brewfather calculations I’m using 187g of DME for one packet of Saflager S189, but I daren’t fill the specified 1.9 litres of water into my 2 litre Erlenmeyer as that will have me scrubbing the hob again this afternoon. Instead I made do with around 1.7 litres, and even that needed to be removed from the heat and rushed to the sink as soon as it started boiling. Having cleaned the outside of the flask I repeated this step once more and called it quits – the DME looks to have fully dissolved and is probably sterile now, which is all the boiling does anyway.
Chilling the flask in cool water for an hour did little to bring the temperature down, but that’s to be expected as we’re in the middle of a heatwave (22℃ outside – woo!) so I left it in the fridge for a couple of hours before pitching the yeast at 18.3℃ and moving it to the stir plate. That’ll do, pig.
The Next Day
Once again I’m guilty of not letting my starter get to full power before brewing, but it’s got to be better than just sprinkling the dried yeast onto my wort. The starter is now around 18 hours old as I fire up the B40Pro, and has spent the first third of its life on the stir plate and the remaining time on my windowsill around 19℃. The fact that I’m about 200ml of water below the recommended level may have something to do with the slow start, but at least there are bubbles in evidence, and as long as I try to match the pitching temperature to that of the flask it shouldn’t be too much of a problem.