I recently purchased a BrewJacket device. The device cools a carboy to the desired temperature and will hold it at that temperature during fermentation. This is a big deal for those of use who live in southern states where the temperature often gets into the 90s.
All this in pursuit of my first lager brew!!
My immersion cooler can get the wort down to about 70 degrees, possibly a skosh lower. The BrewJacket cooling is a very slow process – it took about 39 hours to go from 70 degrees to 45 degrees during a test. The carboy is sealed but I am concerned about infections.
Two questions …
Should I wait until the wort is cooled to pitch the yeast or pitch at the higher temp and let it work as it cools down.
Assuming that I do not pitch the yeast immediately, should I aerate the wort after it has cooled down to pitching temp. This would be possible since I use an aquarium pump with a filter.
Hopefully the voice of experience in this group can provide some guidance.
There are many on each side of both issues. Here’s where I stand:
I prefer to pitch at the desired temp vs pitching a few degrees warm. I can’t say I’ve never done it, but I prefer to wait. Though I’ve not had an issue when I did pitch warm, I believe undesirable flavors could result. However, I’ve not had an issue when pitching the few degrees higher than optimal temp the few times I’ve done it.
I also suffer from warm southern ground water and I ferment in an old refrigerator. The old fridge does a pretty good job of holding a temp once it gets there but like your new device it takes a while to get there. …so I rarely pitch immediately. I normally wait several hours and usually overnight before I can pitch yeast. Again, I’ve not had an issue and feel safe waiting.
As I understand it, many don’t chill at all and wait days to pitch with no ill effects. I’m not sure I could go as far as the Australian no chill method but I do wait.
I’ve read somewhere that aeration should come after pitching yeast — like three days after. I’ve also read that most aerate then pitch. To be honest, I am not sure but I would wait to aerate until the wort is pitching temp.
It’s generally not good practice to drop the temperature with active yeast. Plenty of people do it and get away with it though. I’ve gone 24 hours while chilling to pitch temp with no problem. 39 hours isn’t ideal but you should be ok. Just keep everything clean and sanitary. And you don’t need to go down to 45° for a lager. Low 50s is fine.
Don’t aerate until you pitch the yeast. Without yeast to consume the oxygen there’s no benefit to it.
I am not sure what yeast you are using but you may not need to drop it 45F. I have been fermenting lagers at 54F lately with no ill effects. Others on the forum have been going even warmer.
Even up here in Ohio I can only get away with groundwater temperature, as is, a few months of the year, and just for ales. You can seriously improve the cooling ability of your immersion chiller by running a “pre-chiller.” Just a second immersion coil, basically. Tap water runs through the first coil, which sits in a tub of ice water, and from there to your immersion chiller. Have a few bags of ice on hand and keep topping up. It’s the only way I can get close to lager pitching temperature most of the time, and then just a few hours in the fermentation fridge gets it the rest of the way. Could cut many nervous hours off your wait until you can pitch.
Should I wait until the wort is cooled to pitch the yeast or pitch at the higher temp and let it work as it cools down.
It can be done either way, but the cooling time should be less than your yeasts’ lag time, i.e., the wort should be at your desired ferm temp before the growth phase begins, because that’s when all the flavor-active stuff (both good and bad) get made. If you’re seeing signs of fermentation after 10 hrs but the wort is still at 64 because the brewjacket cools so slowly, you may get a more estery lager.
Should I aerate the wort after it has cooled down to pitching temp?
Aeration should be done immediately before or immediately after pitching. You want to the yeast to mop it up quickly to make them happy but also so that the O2 doesn’t have a lot of time to react elsewhere. Also, the O2 will off-gas a bit, so if you aerate but then wait 24 hrs to pitch, the yeast will have less O2 than you intend.
I used to worry about delaying my pitch for the same reasons. But I almost exclusively brew lagers now and my method is to chill to 70F with the IC and stick it in my lagering fridge and pitch the yeast 12 hours later, I’ve yet to have any issues with infections.
It’s worth noting that folks who are intentionally infecting beers with bacteria to sour them have to keep the wort between 100-120F for days for it to grow.
If your sanitation is good and you have the temps headed towards 50, I suspect the risk of infection is very low.
If you do decide to pitch warm make sure you don’t skip the diacetyl rest. I personally think many lager evils can be cured with a few days at 65F at the end of fermentation.
I also oxygenate with pure O2 just prior to pitching.
I’m way up in Northern Maine and I can’t use my immersion chiller in the winter because the water coming out would turn my driveway into a skating rink. In the summer I run the water into buckets and use that to water the garden. Waste not want not…
So I did buy a 5 gallon plastic jerry can at Walmart for like 7 bucks and I let the wort cool in the kettle a bit and then run it into the jerry can and top it up with distilled water if necessary. If it sits in the garage overnight it’s down to pitching temp the next day. Haven’t had any issues.
Even for ales, I sometimes need to use a pre-chiller like Rob describes because my tap water varies from around 43 F in March/April to around 73 F in August/September. I’ve used a two-stage or two-step chilling process where I chill/recirculate/whirlpool wort in the BK to 90-100 F using tap water, then set up a cooler with ice water and use a pump to recirculate that through the chiller to get down to the desired pitch temp. I’ve done this with both an immersion chiller, and with a counterflow. I find it to be quicker than using a pre-chiller. I sometimes have to add some ice during the second stage/step to keep the ice water cold. I have a serving fridge that has a freezer on top so I make ice in plastic 1-gallon milk jugs to use for chilling.
That is a great idea. I’ve found that bigger ice cubes work better than small ones in my pre-chiller tub; they take longer to melt, and of course it’s the actual melting that removes heat. Can’t get a much bigger ice cube than that.
