Brewing With Total Confidence
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Discussion in 'General Brewing Discussions' started by Gary C., Dec 8, 2017.
Well said Nosy , like so much in brewing there's no single one size fits all method
ok back to the original post before the big debate , most yeast will work fine but it really depends on what you want out of the beer, if your looking for a hoppy beer, US05, BR-97, Nottingham, wlp099, wp007 to think of a few
I don't know what this issue is...just follow the directions on the packet. Danstar yeast packets direct you to rehydrate while most Fermentis yeast packets direct you to just sprinkle that pixie dust right on the wort.
And I don't buy this yeast kill hypothesis. Someone show me the research by a lab or an actual scientist that proves this hypothesis. I've not been able to find a credible source that can prove this and suggesting that wort is toxic to yeast is like saying water is kills fish. Professional brewers wash their yeast with phosphoric, citric, sulfuric, or tartaric acid to kill bacteria and these solutions have a ph as low as 2.
^^^^ Then don't buy it. And try Google Scholar for the articles. I'll help you out: Google "yeast cell death from osmotic pressure." We rehydrate to reduce osmotic pressure on the yeast cells as they're reviving from their dormant state. And as long as you're making beer you like, you're doing it right.
More to do with osmosis than ph as far as I understand it, a high og liquid won't let the yeast rehydrate as well. Try a speriment if you don't believe me, pitch to syrup then to fv, don't blame me for the stuck fv.
I didn't even know about Osmotic Pressures an hour ago. Thanks for directing me to this topic. I just read an article titled "Sequence of occurring damages in yeast plasma membrane during dehydration and rehydration: Mechanisms of cell death"
Really fascinating, here is a bit of the article I found to be the most salient:
4.4. When do cells die during osmotic treatment?: a hypothetical mechanism leading to cell death
Our study results allow us to propose a mechanism leading to cell death during the dehydration–rehydration process. We have been focused on membrane physical changes during the treatments to propose this mechanism. We dismissed a hypothesis of a possible toxic effect of glycerol entry into cells. In fact, glycerol is the main synthesised osmolyte in yeast . Moreover, this is a compatible solute, meaning that it is a neutral substance expected not to be toxic for enzymes in the cytoplasm  and the quantity of glycerol a yeast cell can accumulate is very high  ; . For example, Wojda et al.  report an intracellular glycerol concentration of 900 μg/mg protein in a wild-type strain of S. cerevisiae. In addition, the fact that glycerol provokes osmotic stress for yeasts has been proven many years ago . In one of our team's earlier study , 90% of yeast survival could be obtained after an osmotic treatment at 100 MPa in a glycerol solution by increasing slowly the osmotic pressure. Therefore, it is improbable that glycerol is toxic for yeasts and as far as we know, such a toxic effect has not been reported in the literature....Thus, there is a rehydration level, at 20 MPa, at which the percentage of cells with intact membranes is maximal.
Anyone want to calculate the osmotic pressure of the yeast cell membrane in their wort?
Nah. I'll just rehydrate my dried yeast.
And aim for less than 20 MPa of pressure on the cell membranes. This is a factor in large conical fermentors too, by the way....
Osmotic pressure and Hydrostatic pressure are not the same; though both are measured in the same units.
We homebrewers have to do a lot of things on faith and then judge the results for ourselves. I've never been too interested in getting into the weeds of the osmotic process, but the rehydration/better cell count hypothesis seemed sound and my results have been consistently better as a result. I think that once we choose to skip the starter, we need all the help we can get. We should all be using "pro-brewer" yeast pitches if we want to make the best beer possible in the shortest possible time, but there are so many other small impediments that we may or may not see a return on the extra cost/time/labor of a double to triple pitch or 2 stage starter for typical ales. We just take longer to ferment and wait longer to drink.
I was just giving Jeff a hard time since he loves people who says there is only one right way to do things.
I rehydrate though but I know folks and don't and their beer turns out fine.
It's all in what you like. I like clean so the ester production of an underpitch isn't my thing - and directly sprinkling dry yeast on the wort is an underpitch. I think if there were an absolutely right answer, if there were such a thing as True Beer (TM), we'd have found it in the 14,000 years humanity has been trying to make it. Bottom line is there is no "right" way. There are only recommendations and if you're making the beer you like, you're doing it right.
I didn't see it mentioned, but I'm a big fan of Denny's fav 50 (wyeast 1450) in my pales and ipa's. I think it's a largely overlooked yeast. I'm guilty of overlooking it myself, but always happy with the results when I do!
Yeah...Jeff gets a little prickly when he senses things are getting dogmatic. Keeps us all in line.
I just don’t think we’re doing any favors to anyone when we say that there is only one correct way to brew beer. There are many different methods, and I’ll gladly drink any of your beer, even if you are brewing wrong!
I am just trying the hop combination from Ozaeks Sierra. I have run out of grain and specialties so just using Maris and Carapils. I have stock waiting for me in Brisbane next week and will have a big shopping spree to last for another 6 months.