Slow Fermentation?

The number of packets of yeast are irrelevant as yeast will reproduce until they eat all the sugar whether you start with one packet or five. The amount of nutrient will depend on the volume and gravity of the must.

Yeah it's done that to me more than once. I expected them to finish off and leave a bit of sweetness, but no, the FG ended up at .990. The little basetards ate every last scrap of sugar they could find, giving me an ABV of 17.06% and a 17+ month aging time as well. I was aiming for dry anyway, just not Saharan like dryness. We'll see how it bulks for a while, then I'll decide on back sweetening a bit if at all. Probably keep it as is...

DHicks908 said:

so here is what I was pondering... is the nutrient content just based off of the volume of the must or does it have a correlation with how many packets of yeast you use??? more yeast need more nutrients, or is that a bad way to look at it??

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I could be wrong here. And if I am please someone say so. But, I believe that the yeast will naturally stop reproducing accordingly once the "right population" level is reatched. I think when we add more packages up front it just gives them more man power to do the work as well as more soldiers to fight off the bad guys. I have never read anywhere, that the amount of food is dependant on populations. So far I have only read based on volume of liquids.

DHicks908 said:

Happy holidays everyone! So yesterday was day 14 of fermentation and it began to slow down heavily. I racked into a clean glass carboy and topped it off with approx half a gallon of fresh cider. Fermentation picked up almost right away... but now I am curious if it is at all possible to accurately check my SG, considering I altered the overall volume of the liquid and the concentrations of all the sugars, etc. ???

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Here's a suggestion. If you just continue to add honey untill the yeasties all croak you can just imagine then, that the ABV% is somewhere close to the tolerence level. I don't care personally if I'm one or 2 points off. It's (in my opion) the FG that makes it drinkable or not. That's why I suggested at the top of this thread, to start with a lower OG so your ferment would go smoothly, and then add the rest of your recipies honey amount after your midway into your ferment.

Volume of must and gravity along with the specific requirements of the yeast strain used are the key determinants of nutrient amount needed. The quantity of the yeast pitched really isn't so important. In fact, with a large biomass yeast pitch (5+ g/L) you can ferment without nutrients - one trick for successful "show meads."

Medsen Fey said:

Volume of must and gravity along with the specific requirements of the yeast strain used are the key determinants of nutrient amount needed. The quantity of the yeast pitched really isn't so important. In fact, with a large biomass yeast pitch (5+ g/L) you can ferment without nutrients - one trick for successful "show meads."

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I have been searching all over the `net trying to find a method for fermenting show meads but have been coming up short. THIS ^^^^ is exactly what I was looking for. 5+g/L must. Got it!!! Thanks Medsen!!

You can also boost a show mead using a technique where you add 2.5 or three grams per liter of wine or bread yeast rehydrated in boiling water, and then adding 0.25 g/L of wine yeast when the temp is down to 104F. Then pitch after 15 min. If you select a low-nutrient requiring yeast, and use a pollen-laden unfiltered honey it can work.

Hijack has been moved: Click me!!

DHicks908 said:

so here is what I was pondering... is the nutrient content just based off of the volume of the must or does it have a correlation with how many packets of yeast you use??? more yeast need more nutrients, or is that a bad way to look at it??

Click to expand...

The amount of yeast is not a determining factor in this. You can start with one yeast or 50 million and you'll stil end up at the same place. More yeast just makes it easier to get through the process without problems. It gives them an advantage against the bad/wild yeast.

Read this!


This is my approach (and although there are similarities to other nutrient methodologies, we do differ somewhat). It agrees for the most part with the recommendations of Lallemand and other commercial yeast manufacturers.

First, I make an assumption that the honey that I use in any of my musts provides negligible amounts of YAN.

Next, I determine what (if any) fruit I will use in primary fermentation.

Then, I try to find out (for melomels) how much YAN is present in the fruit I plan to use (measured in ppm, for the given volume of fruit I'll add in primary). If I can't find info on YAN for my particular fruit, I assume a baseline value of 100 ppm. That's close enough for gov't (and mead) work.

Then I work out the dilution of that fruit-supplied YAN in my total volume of must. If for example I am mixing up a 5 gallon batch of must, and one gallon is pure fruit at 100 ppm, then I will dilute by a ratio of 1/5, so the net YAN in my fully mixed must is 100 * 1/5, or 20 ppm.

I next find the nitrogen requirements of my yeast. For most commercial yeast strains we only know if the demand is low, medium or high. For low demand yeasts, I ensure that the total YAN is 225 ppm. For medium demand yeasts, I ensure that the total YAN is 300 ppm. For high demand yeasts, I ensure that the total YAN is 350 ppm. These are numbers that I've found through trial and (mostly) error that will produce clean ferments with minimal H2S production in my meads.

Note: Those values are what I use for "normal strength" meads, which for me are musts that range in initial gravity from 1.080 to 1.100 (Initial Brix range of 20 to 24). For initial Brix of 24 to 27 (SG from 1.101 to 1.115) I multiply my normal strength numbers by 1.1. For Brix from 27 to 32 (SG from 1.116 to 1.140) I multiply the normal strength numbers by 1.25. For initial gravities in excess of that, I wing it.

I calculate how much Fermaid-K and DAP to use knowing that Fermaid-K has 13% YAN by weight and DAP is 21% YAN by weight. Another way to express the YAN content of those is that 1 gram of Fermaid-K provides 130 ppm of YAN to a single liter of must, and 1 gram of DAP provides 210 ppm of YAN to a liter of must.
Last edited by wayneb; 02-17-2010 at 04:23 PM.