Do you aerate your wort if using a yeast starter?

[tjsopcak]

The reason I ask is because I had read a few posts on Homebrewtalk.com stating that there is no need to aerate wort if using a yeast starter since the yeast have already taken all the oxygen they need and are now in growth phase.

This may be a similar idea as adding Olive Oil to a yeast starter and NOT directly into the wort.

Mention was made that aerating the wort before pitching when using a yeast starter is possibly a bad thing since you are simply adding oxygen that is no longer needed and may actually lead to oxidation.

Any thoughts on this and how many of you use yeast starters AND aerate your wort prior to pitching? Also, what method of aeration do you use?

I currently use a whip drill attachment or simply shake if pitching into a 3 gal carboy.

[Harbicide]

As I make either 15 or 20 gallon batches my starters are between 2 and 3 gallons (depending on whether the beer is an ale or lager); I always oxygenate. The reason is the starter is only for the growth of yeast. The newly created yeast still needs oxygen to continue respiration and further growth.

Even with a 3 gallon batch I would still recommend oxygenation.

My method of oxygenation is an aquarium pump through a sterile filter. I pump until the foam reaches the rafters (just kidding). I can't say I've ever experienced oxidation of the resulting beer.
_________________
There is no strong beer - Only weak men.

[Danny]

I always aerate my wort prior to picthing. I also use medical oxygen in a 6 gal carboy.
In my opinion by using a starter that was oxygenated and aerating prior, the amount that would be in the starter will most likely not be enough to cause oxidation of the beer.

[claytr]

I used to use oxygen, by the way there is no difference between medical and non-medical oxygen they both come from the same tanker, just ask who fills your tank the next time. What I do now is as I pump out the wort I run it through a small metal strainer as it goes into the bucket which puts plenty of air into it, then dump it into my conical.

[riffhead]

Like Harbicide said, the yeast are going to need oxygen to further grow and complete fermentation, so aeration is needed to ensure you get a clean ferment. Even though the yeast are active and have increased in count in the starter, they are going to do a lot more reproducing during fermentation. This is similar to how dry yeasts don't need to be started, but still need to be pitched into an aerated wort. The manufacturers make sure the yeast cells have all they need to start fermenting, and that the number of cells in the packet is large enough to ferment 5 gal of average strength wort.

I do 10 gal batches and aerate with oxygen for ~2min and noticed improvements in fermentation over just shaking or splashing.

[claytr]

If you do go the oxygen route, just do not over do it, because too much oxygen can be as bad if not worse than not enough

[tjsopcak]

Well, so far I've acquired plenty of info to steer me to continue wort aeration even when using a yeast starter. Thank you all for your help to debunk what I had read on HBT that aeration is not needed and possibly detriment when using a yeast starter.

Do any of you know of a source for good quality and low cost oxygen tanks, regulators, and diffusion stones for aeration? I know there are numerous online sources but unsure whether there is a local supply store or preferred online retailer for these items.

[riffhead]

For the tanks you can get them at Home Depot relatively cheap. The only place I could find the regulator was online at Williams Brewing. They also had the diffusion stones.

[tjsopcak]

Thanks riffhead. I completely forgot about Home Depot as a source as I was only thinking of medical grade O2 tanks but I honestly don't need that large of a tank nor would I find it easy to have them refilled. I'll try the route of Home Depot for small oxygen tanks.

I've found the regulators on NorthernBrewer MidwestSupplies, etc. I'll have to check out Williams Brewing again as I never bought anything from them yet.

[tjsopcak]

An additional question related to this topic. While it's obviously a great idea to provide needed oxygen to the wort for yeast consumption, how much of a factor do you think it is to aerate via oxygen tank/diffusion stone when not yet having the ability to regulate fermentation temps?

I currently rest my primary on the basement floor which fluctuates from 65-72F throughout the spring and summer months. I don't have issues with fermentation but I'm sure I get more byproducts than desired by typically fermenting at temps above those recommended per yeast strain.

[claytr]

RE Regulators. I pick up O2 and Propane regulators (The good ones that welders use) either at Rogers Ohio, and farm auctions. You can get these for $10-$15 each, and they are much superior to anything you will find in a brew store. E-Bay and Craigslist sometimes have them too. Also some of the new propane regulators are a pain, because of the safety valves. Once you turn them down, you cannot turn them back up without turning all the way off first, then you have to relight.

[Harbicide]

[tjsopcak]

Thanks for the input. Just trying to determine whether I want to invest in an O2 regulator, diffusion stone and disposable tank before I had a temp controllable fermentation chamber. I may very well do so as I had really wanted to but decided to focus funds elsewhere which was a sump pump for immersion cooling and future carboy/corny cleaner.

[riffhead]

Basically when it comes to fermentation all of those things are factors (pitching rate, oxygenation level, and temperature) and the more control over each the more repeatable your fermentations will be. Before I started fermenting in a fridge, I had alot of trouble getting ferment temps below 70. I found that if you use a strain like White Labs 001, or Safale US05 that ferment pretty clean, then you wont have as much issue with too much ester production in that temp range. But definitely pitching enough yeast, and aerating/oxygenating enough are important too.

[tjsopcak]

How long to you aerate your wort with oxygen tank/diffusion stone? I'm sure that I read an article or forum posting somewhere else about this but curious as to know your personal experience.