So I've got an Imperial Stout bubbling away (24hrs in at 8pm on Monday). This is my first time using any sort of temperature control, not counting closing or opening the one and only vent in my brew room, so I can set the temp to whatever I want. The fermentation chamber is set to 63 and the little thermo strip on the side of the carboy reads 63. I know inside the wort it's probably warmer but is the 63 ambient too cool to encourage full attenuation? The stout clocked in at 1.082 OG and I pitched two packs of properly rehydrated S-05. This is the "biggest" beer I've done to date so fingers crossed.
after 48hrs the bulk of the flavor esters have been made, I would recommend raising it up to 68 after that.
It wouldn't hurt to raise the temperature toward the end, to speed things up. But there's no reason it shouldn't finish at 63F.
If anything you may be too warm. I'm guessing you want your US05 to be working around 64-66. The heat of fermentation will add ~4-6 degrees so your wort is pushing that limit. Remember, the yeast love the warmer temps, it's the drinker who wants it cooler. To get a better feel of wort temp try to cover your thermo strip with bubble wrap. Hopefully this will give some indication of wort temp. Consider a thermowell, they are cheap and effective. Your ester profile is largely determined in the first 72 hours of fermentation, raising your temp after this time should help the yeast finish with little danger of off flavors. Whatever you do to prevent diacetyl, avoid ytuo.
Not exactly. Most esters are formed later, from fusels and other alcohols. It fair to say that the stage for the final ester profile has been largely set in the first few days though.
Thanks guys. I'll raise it up to 68 Wednesday night. Guess I'm a bit gun-shy with stouts/porters though there's no reason I should be. The first brew I ever made was a porter and it never went past 1.024 (1.050 OG) and tasted like shite. Think I'm just paranoid of repeating that experience.
I keep it at 62-64 for my big stouts for the first week roughly. Then I give them a slow ramp to 67-68, to sit for another week or two. I did this on the last 1.115 OG stout and got it to finish around 1.023. Kept it cool to keep the fusels and esters down. I'd say you are okay. Give it a week and allow it to warm up as it's finishing.
