# How often to add Yeast Nutrient?

### Help Support Homebrew Talk:

##### Member

Now that I have actual yeast nutrient...do I add more or was the 1/2 cup hot water water and single packet of yeast enough?

If I do add more, how much and how often?

Many thanks!

#### Maylar

##### Supporting Member
HBT Supporter
If you're ferment has been going for 4 days or more I wouldn't add any more. If less than that, one tsp per gallon. Only once.
Have you acquired a hydrometer yet?

OP
M

##### Member
If you're ferment has been going for 4 days or more I wouldn't add any more. If less than that, one tsp per gallon. Only once.
Have you acquired a hydrometer yet?
I am purchasing one today, whether in store or online. Don’t know what to do with it though

#### bernardsmith

##### Well-Known Member
I don't know any hydrometers that come with instructions so you might want to watch some Youtube videos about how to use one but basically, an hydrometer measures the density of a liquid compared to the density of pure water. Pure water has a nominal density (AKA specific gravity) of 1.000 and when you add sugar the density rises. Adding 1 lb of sugar to water to make a total volume of 1 US gallon raises the density of the water by 40 points (approximately) so the hydrometer will read 1.040. A starting gravity of 1.040 - if the density has been increased with sugar - will have the potential to result in a wine with about 5.25 % alcohol by volume (ABV) if you add (pitch) yeast in this sugar -water solution. As the yeast ferments the sugar the density will fall and as alcohol is LESS dense than water the final density COULD fall below 1.000 - to something like .996 or .994 but it might stop at 1.000 and it may even cease above 1.000. Final gravities ABOVE 1.000 are likely to taste sweet, relatively speaking, while final gravities below 1.000 are likely to taste quite dry.

Maylar's point about 4 days is to suggest that all other things being equal, when there is about 9% alcohol by volume in solution (so the yeast is fermenting about 2 lbs of sugar per gallon of liquid) the yeast cannot consume the nutrients and if you add them at that time they will be a food source not for the yeast but possibly for bacteria and other undesirables.

#### Dan O

##### Supporting Member
HBT Supporter
I don't know any hydrometers that come with instructions so you might want to watch some Youtube videos about how to use one but basically, an hydrometer measures the density of a liquid compared to the density of pure water. Pure water has a nominal density (AKA specific gravity) of 1.000 and when you add sugar the density rises. Adding 1 lb of sugar to water to make a total volume of 1 US gallon raises the density of the water by 40 points (approximately) so the hydrometer will read 1.040. A starting gravity of 1.040 - if the density has been increased with sugar - will have the potential to result in a wine with about 5.25 % alcohol by volume (ABV) if you add (pitch) yeast in this sugar -water solution. As the yeast ferments the sugar the density will fall and as alcohol is LESS dense than water the final density COULD fall below 1.000 - to something like .996 or .994 but it might stop at 1.000 and it may even cease above 1.000. Final gravities ABOVE 1.000 are likely to taste sweet, relatively speaking, while final gravities below 1.000 are likely to taste quite dry.

Maylar's point about 4 days is to suggest that all other things being equal, when there is about 9% alcohol by volume in solution (so the yeast is fermenting about 2 lbs of sugar per gallon of liquid) the yeast cannot consume the nutrients and if you add them at that time they will be a food source not for the yeast but possibly for bacteria and other undesirables.
That has to be the easiest to understand explanation I've seen yet! @bernardsmith. As someone who has only been making mead since July 1 2020, I come here every day & learn something new. Sometimes it's something really small, but, other days it's more. You, sir, are a constant wealth of knowledge. Thank you.