Relatively new home-brewer… I’m working on my third batch ever right now. For fermentation, I use a plastic bucket and I’ve only made 5 gallon batches. My beer typically stays around 65-68 degrees during fermentation. I’m hoping to get some input on the benefits of dry yeast vs liquid. So far, I’ve only used dry (mainly due to cost and simplicity). But are their benefits/downsides to using either? Is liquid yeast better?
Also, I was hoping to learn more about aeration. Right before I pitch my yeast, I try to rock my fermentor back and forth a bit to aerate the wort (per the directions). Is this necessary? What does this do?
Rocking back and fort give o2 to the yeast. Or you can add oxygen to your wort. So your yeast can do its thing. The easy part of dry yeast. Just sprinkle it on top of your wort. If i do you dry yeast. I rehydrate a bit. Some water. And make a slurry of your yeast. Me use mainly. A. Yeast starter. With liqued yeast. So you create more yeast cells. Before you pitch. Into your wort. This involves. Bit more work. Boil some water. Add dme. Cool down. And add the yeast. To the flask. Me do use stir plate. For about 30 hours. Or some members here. Do you use the shake and stir method. Insted of stir plate. You can even use a smack pack of liqued yeast. Shake smack untill pack is inflated. And pitch your yeast pack
Welcome to the forum @sambre.
The yeast need oxygen in the early stages to be healthy and multiply. So you introduced as much as you can. Rocking on its own might not be enough unless it’s violent. You are trying to really get that air in there. I make an effort to really introduce the oxygen to the wort while filling my bucket the first time from my brew kettle. If I need to top off or add water from my sink I use my kitchen faucet on its spray mode and really whip that wort into a froth. These two ways are enough for my process and I don’t shake many batches any more.
I use dried yeast almost exclusively. I too sprinkle on top and then just rock the fermenter a little bit, NOT to aerate, which is NOT necessary for dried yeasts (another advantage!), but just in order to spread it out. There are so many advantages to dried yeast that I just probably will continue to use it for almost every batch. The only exception is a few particular yeasts where there just is not dried substitute. But those are becoming fewer and fewer, as new dried yeasts continue to be released.
As far as aeration I pour the wort from the kettle through a strainer then pour back and forth in a couple buckets. I didn’t know you didn’t need to aerate dry yeast
The book Yeast will tell you most everything you ever wanted to know about the subject. At the start, yeast eats up all available oxygen to reproduce. More yeast means a better and faster starting fermentation. The book recommends about 45 seconds of oxygen injection for the basic 5 gallon homebrew batch. I have been using our host’s oxygenation kit for some time with definitely noticeable results.
Although pure O2 injection is best method, according to the book anyway, any method to get air or oxygen in at the start of fermentation is a good thing.
It’s important to note however, that after that time, oxygen is a bad thing. Your fermented beer will oxidize and not taste as good.
@dmtaylo2 Can you tell us more about not needing to aerate dry yeast. That’s news to me too
As a bubble rises through your wort or fish aquarium it doesn’t really get smaller. Not THAT much oxygen is transferred. The key is to create the greatest surface area possible to maximize transfer. So thousands of micro bubbles through a diffuser creates a huge surface area when compared to the same volume in bigger bubbles
When brewing pale ale and such I just US-05. Everything else I’ll use liquid. That said I have used alot of other dry yeast with excellent results but for the original post I would recommend to any new brewer just use dry yeast to start and master the craft before worrying about the yeast. If your beer is coming out crappy it’s probably not because you used dry yeast
“The purpose if aeration is that the O2 is used by the yeast to synthesize sterols. Those keep the cell walls flexible to encourage budding.”
From another guy:
“The oxidative growth technique used to produce dried yeasts actually helps to stabilize the cells against the dehydration process, in part by increasing the production of these compounds (by up to 5 times).”
From Lallemand:
“The yeast contains an adequate reservoir of carbohydrates and unsaturated fatty acids to achieve active growth. It is unnecessary to aerate wort upon first use.”
Source:
And this is just one source of hundreds of others I’m sure.
I should probably run an experiment on this sometime. It would be super easy. I use dried yeast most of the time anyway. Split a batch, aerate the bejeezus out of half and leave the other half alone. Taste the final beers. Hmm. This experiment might be in my near future. Maybe.
I use both, probably about 60/40 liquid to dry. I keep a spare pack of both ale and lager dry yeast on hand always just in case.
Rehydrating dry yeast is another nuclear topic, like throwing rocks at a hornets nest. I do rehydrate, but I think I saw a recent expert opinion stating that the need to rehydrate is a myth also…
And for some of the same reasons @dmtaylo2 detailed above you do not need to make a starter with dry yeast. Just like oxygenating, it adds another unnecessary step. Pitch 2 or 3 packs for a big beer or >5 gallon batch as directed by a yeast calculator.
I did a side by side using US-05 wort from the same batch. 6.5 gal glass carboys with 5 gal in each. I rehydrated one packet and just dumped in the other. Fermentation started about the same time. Ended about the same although I don’t keep watch, just let it go a couple of weeks minimum. FG same. I did not notice any difference in the beer really and it wasn’t a very scientific test. I just wanted to know if rehydrating was worth my time an effort.
Bottom line was that unless it will be a high gravity beer, just dump the yeast in. YMMV
I read an article/ad in BYO by Lallemand and it showed scientifically that the dry yeast didn’t need O2. But it didn’t hurt either.
And @dmtaylo2 is correct in his cites as well as @denny. The dry yeast is produced with glycogen, nutrients, carbs, and fatty acids which means it doesn’t require O2.
It also showed no substantial scientific data to recommend rehydrating.
@Steve the ‘more is better’ is not always accurate. There are studies that indicate that too much yeast can create significant esters and off flavors as the yeast don’t replicate enough to clean up byproducts. @denny has a cite for this as well.
