Brewing now. Was going to hit fresh 0xygn through the chiller. I just don't know how much or how long to give it the oxygen for. Any help? Thanks
Yes, go post chiller. How long is the hose from the chiller to the fermentor? The longer it is then the more chance of the bubbles totally dissolving into the wort and not going into the head-space. One problem is normally when people don't have a flow meter they just eyeball the amount of bubbles and keep to that amount for repeatability, you don't have that capility. Also from playing around before I was able to quantify the flow I noticed that most people will find the compromise between amount coming and amount of foam. Matching that to looking at my stone when metered, I can say that most people oxygenate around 1-1.5 liter/minute. The normal rates are usually quoted in 1 l/m, so many people might be overshooting their goals, but a lot of that goes into the headspace. These quoted numbers might be for 100% solubility. If you don't have foaming out of the hose then for normal gravity beers I'd feed it w/a aquarium pump and run it 100% of the time. For pure oxygen and without a flow meter it's best guess. I'd going with two minutes.
Oxygenating any wort that is over 80 F can be consider hot side aeration. This can cause off flavors and darkening of the wort. I would check you temp coming out of your chiller, to make sure it cool enough to oxygenate. The gravity of the wort also play a role in time/how much oxygen is required. Happy Brewing!
thanks. I actually oxygenated the wort as it was coming out of the chiller into the fermentator. It was at around 70ish. I gave it 2.5 minutes with the oxygen for a 8 gallon batch of a RIS that was about 1.092. I hope that was ok.
without an O2 meter there is no way to know how much dissolved oxygen is in your wort. there is no way to know for certain when you have achieved 12 ppm for example. the answer to your question "how long?" is mostly an educated recommendation. an O2 meter starts at about $700 and they are one hell of a tempermental bastard to maintain. a flow meter does not help. it won't tell you anything about the dissolved concentration in wort and that is all that matters. answer: more than 1 minute up to 2 minutes. there is not much downside if a homebrewer supersaturates with O2, so go ahead and run your stone for 3 minutes if it will help you sleep. allow oxygen to flow into the headspace of your bucket or carboy as well. Cheers.
I disagree that a flow meter won't help. It's been published what flow rates will yield in ppm. Yes it's not exact and there are things that effect solubility, but it will help with repeatability and doing it in-line will help the process to be more accurate.
