I can’t envision why yeast nutrient would aid lag time. In that early stage, yeast are just acclimating and not actually reproducing in great number or exhausting their internal nutrient stores.
With regard to zinc, many raw water supplies have zinc in them. But if you’re using RO water, any zinc that might have been in the water is gone due to the RO process. Adding zinc is an important necessity when brewing with RO water. Eventually, your yeast will run out of zinc and this ferment or future reuses will suffer.
+1 Martin. I use zinc nutrient, because I serially repitch and brew with RO and add back minimal salts in my lagers. Somewhere (Dr. Bamforth maybe?) I read or heard that zinc was helpful, so I just always add it as my last ingredient in the boil.
Well, while I realize it’s anecdotal, all I know is I get faster starts, more vigorous fermentations, and faster complete finishes with nutrient.
I found it is more advantageous to add it to the FV vs the kettle. I didn’t understand why but I’ve read the nutrients get bound in the trüb and I like to transfer clear wort from kettle to FV.
Nutrients are not always necessary according to Chris White in his book about yeast. However, as I recall, and I’m paraphrasing here, he says using nutrients will not hurt and it’s better to be safe than sorry. So, I add 1/2 tsp of nutrient in the final 15 minutes of the boil with every batch. The product I use is made my White Labs. I figure: why not? Now, maybe Chris made this statement to sell more nutrient…maybe??? :
I don’t understand - why would aeration NOT be necessary with a dry yeast over a liquid yeast? I aerate my wort regardless of the type of yeast I use. Is it not necessary to aerate with dry yeast?
Per the Lallemand website, their Fermaid K should be stirred into the Wort just prior to yeast pitching. I believe that boiling it destroys much if not all of it.
[quote]For normal applications, the recommended addition rate of Fermaid K is 25 grams per 100 liters.
Fermaid K should be dispersed (stirred) into the wort just prior to pitching the yeast.
[/quote]
Both Lallemand and Fermentis now advise that it is not necessary at all to aerate the Wort prior to pitching their dry yeast products. That requirement is now the sole domain of liquid yeast. They are both OK with direct pitching without rehydration now also, after both did studies which concluded that there is little real world benefit gained by rehydration (after decades of saying that rehydration was a critical requirement).
Old habits die hard and especially in the homebrew community it seems that if you challenge a method that someone has been using for a long time… often a method taught to them by someone they consider “expert”, they tend to react defensively.
It has to do with how the yeast is dried. From lallemand:
[quote]BRY-97 yeast has been conditioned to survive rehydration. The yeast
contains an adequate reserve of carbohydrates and unsaturated
fatty acids to achieve active growth. It is unnecessary to aerate
wort upon first use.
[/quote]
That’s fascinating information. Do either of these manufacturers give a logical reason why it’s not necessary? As I understood, oxygen is required for the yeast cells to multiply. Now you have me thinking…
Aeration is required such that certain aerobically produced lipids called sterols which are required of the yeast as precursors in order for them to produce alcohol get adequately produced by the yeast. No sterols, no alcohol production. Both dry yeast manufacturers state that fully sufficient of these requisit sterols are present within each package of their dry yeast.
Because when dry yeast is produced, it’s growth is stopped during sterols production, so it’s loaded with sterols. The purpose of aeration is to allow the yeast to produce sterols. If they’re already there, there’s no need for aeration.
That makes sense. I find it odd, however, that this discovery is recent. I suppose it’s all part of the “science” aspect of this hobby and science is discovering new things every day.
I think there are 2 things at work here…the method of producing dry yeast has changed over the last 20 years. And there’s a persistence of dogma in the homebrew world that tends to make many homebrewers resistant to New info. I know I got a lot of pushback after posting info about rehydration and aeration that came directly f4om biologists with the companies. Many homebrew “experts” simply repeat what they’ve heard without testing or looking into it.
Pg. 13 under tips…Active Dry Yeast is rich enough in lipids and minerals for it’s own multiplication process. Also, there is no requirement for adding O2 to the cooled wort.
