I just recently purchased an oxygen tank and aeration stone for my next set of brews. After some research it seems that simply pouring your wort into the carboy and shaking it repeatedly was not sufficient enough aeration. (Still not sure on all the facts). So I ran a little test on my yeast starters one aerated and one was not. The one that was aerated absolutely BLEW UP. The one that was not. Not so much I got some yeasties working in there. But I also wonder if it also depends on yeast strain. Matching. Gravity and volume and temperature. That was the best controls for experiment I could come up with.
Anyone have any thoughts or insight on aeration? (If that is the correct term)
You are not imagining things. As I have started many times, a yeast culture does not need to be spun. It needs to be pitched into well-aerated wort. The amount of dissolved O2 at time of pitching matters. Also, as I have stated many times, there is no magic in an SNS starter. The SNS method of making a starter is little more than a poor man’s O2 bottle. Pitching an SNS starter at high krausen is integral to its performance.
Your starter will be at high krausen way before tomorrow. High krausen is usually reached in 12 to 18 hours, often sooner. I would suggest placing the starter in a refrigerator when you see low krausen forming to retard the fermentation. You can pull it out of the refrigerator when you start your brew day.
yup absolutely. however, i think different yeast strains do have greatly different oxygen requirements. i’ve never had attenuation issues before ever, even on big beers or meads. i am struggling right now with WLP500’s attenuation, and the only variable i’m missing is pure oxygen.
i went out to buy a can of bernzomatic the other day but they were sold out at canadian tire.
what kind of release valve (?) did you use oiscout?
I got a dark mild going with WLP005 I tried 002 and I liked it but I’m experimenting, and that beer is in a bucket so I hadn’t gotten a look at it yet it was trucking earlier this week I’m doing Diacetyl rest on it now
Yes, different yeast strains have different O2 requirements, but most of the strains available to amateur brewers are O1 or O2 with respect O2 demands. How are you aerating? Are you using a venturi? Splash aeration will get one to O1 (half air saturation) at best. A venturi will get one to O2 (full air saturation).
It is a piece of racking with holes drilled downward in the flow of the wort. It functions as a venturi even though it does not look like a traditional venturi. The device is placed vertically at the end of the tubing draining one’s kettle into one’s fermentation vessel. The inside diameter is 1/4". When used with 5/16" or 3/8" tubing, the wort pressure flowing through it drops while the flow rate accelerates. This phenomenon is known as the Bernoulli principle. The result is a vacuum that draws and mixes air through the holes. If used correctly, it will create a head of foam large enough on top of the wort that one will have to slow down the flow in order to allow the foam to dissipate. When dealing with yeast, foam is good.
The good old Bernoulli effect from grade school science. I remember the example as when taking a shower the moving water resulted in lower pressure which would cause the air outside the shower to move towards the low pressure, pushing the shower curtain in. Hence the need for weights on the bottom of shower curtains.
I guess I missed the memo on this, so to speak, Denny - you are saying wort aeration is not a must if pitching dry yeast packet directly into the wort? Please say a bit more…
The purpose of aeration is so that the yeast can produce sterols to keep cell walls inflexible to aid budding. When dry yeast is produced, growth is stopped during sterols production. No further sterols are needed, so no aeration is needed.
that is an awesome concept. yes, i have been shake aerating.
to confirm, you aerate the wort using this effect while transferring the wort from kettle to carboy (fermentor)?
that is a really viable solution for a lot of people, and i might follow this route. first i need to improve my wort chiller though so it gets wort to true pitching temp. not going to lie, i made it myself out of copper tube, and tried to go cheap ($50 CAD total), it works, but it takes about an hour of water running to get it to the right temp… and i usually just chill it to ~50C and let it rest over night.
