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mfalenski
04-24-2009, 10:11 AM
Some sources say to add DAP at the start of fermentation, but not at pitch due to the possibility of the yeast getting burnt by the nitrogen. It also stated to wait 12 hours (I read that as at the end of lag phase) to pitch the DAP whereas at that point the yeast could handle the nitrogen. So, if the lag phase is shortened down to a few hours how should DAP be added?

For a "new" batch I do a rehydration with Go ferm, add Fermaid K at pitch, then add DAP at end of lag. Then Fermaid K and DAP at 1/3rd. Doing daily aererations until 1/3rd, too.

What I have noticed is that when I am pitching onto a previous batches yeast cake, my lag time is down to about an hour or two and I am not sure how to add DAP. Do I still wait a few hours or add then? Or don't worry about it? :) Is there a big difference between "new" yeast and some that have "been around the block" a few times?

Teufelhund
04-24-2009, 11:28 AM
Welcome to gotMead?!

Firstly, do NOT mix nutrient brands. Stick to DAP if you're using , say, Red Star. Use Go Ferm and Fermaid K only with Lallemand yeasts for the optimum results.
Secondly, add the fermaid K at 1/3 and 2/3 sugar breaks. At pitching, the yeasts already have loads to eat. Adding nutrients at the breaks give them that second wind they need to continue growth and yeast hull formation.
Daily aeration X 2 for the first 7-10 days will speed up fermentation so that you're ready to rack into a secondary by then.
"New" yeats vs old yeasts? Depends how old and what type of yeasts. Most can be either frozen or refrigerated for up to several years, although activity will decrease accordingly. I've used a 1118 that was a yr old but still did quite well.
Hope this helps.

DD

akueck
04-24-2009, 01:45 PM
Adding nutrients at the end of the lag phase is a common practice. If that is a few hours for you, don't hesitate to add your DAP then.

Pitching onto yeast cakes is not a common practice in wine and mead, though it is common in ales. The difference is how "tired" (read: close to death) the yeast are at the end of fermentation. In an ale, the alcohol content is generally much lower than the yeast's tolerance and the yeast happily goes into a more dormant state, ready for more sugar to someday appear. In wine and mead, the yeast is much more stressed out by the time they are done, and the alcohol content is so high some (or many) have reached their limit. Dumping them into fresh must is a much larger shock to their system than is adding new (low gravity) wort to an ale yeast cake.

The difference is twofold: if you repitch onto a wine/mead cake you'll be adding a lot of dead yeast, vs ales which most of the yeast is still alive. Dead yeast can vary in flavor, so your results will vary there. Secondly, the yeast that are active after the wine/mead fermentation are not a representative selection of the original strain--they are the ones that have survived in the final mead. This could lead to behavior & flavors that is not what you expect. Again with ales, most of the yeast is still alive and will reproduce the basic characteristics of that strain with greater faith.

I don't pitch onto full yeast cakes with ales myself, but I will sometimes wash the yeast and pitch an appropriately-sized slurry. (Pitching onto ale yeast cakes has its own set of problems, which I can run down for you if you want.) For mead, it's worth the dollar to get a new pack of yeast--you know what you're pitching, you know it's healthy, and you know what to expect.

mfalenski
04-25-2009, 07:39 AM
Rats...I guess I'll have to spend that extra .85 on a new pack of yeast then. :)

I usually do 2 or 3 1 gallon batches with the same yeast mostly because I was testing or
adding to a recipe. Made one that was cinnamon vanilla, then the next was cinnamon vanilla, and orange. Then the next was cinnamon, vanilla, orange, grains of paradise, and clove. (That one needs to age out some!)