PDA

View Full Version : Amount of yeast needed



Asator
01-27-2010, 07:11 PM
Does the size of the batch change the number of packets of yeast needed? Example, if a person uses one packet of D47 for a 1 gallon batch of mead, should a person use more than one packet for a 5 gallon batch?

Thanks,
A

wayneb
01-27-2010, 07:25 PM
Commercial packs of wine yeasts for home users generally are sized for a 5 gallon batch (usually anywhere from 1 to 2 grams per gallon of active dry yeast), designed for use in an average starting specific gravity. If you happen to use a full packet of D47 for a single gallon, that won't hurt a thing (all it means is that fewer generations of yeast cells will have to occur to build up to a stable population), but if you want to go appreciably larger than 5 gallons, or if you're starting from an initial gravity much higher than that typical of wine musts (say anything over 1.115 or so), it would be a good idea to pitch two packs.

You can pitch too much yeast, but generally that involves LOTS of yeast (say 10 to 20 packets into a 5 gallon batch). Likewise, if you pitch too little yeast then the cells need to undergo reproduction for more cycles to build up a stable colony, which could introduce mutations in the population, or if there isn't enough nutrient or oxygen to sustain that reproduction, you'll be left with too few cells to do a good job and the fermentation might stick at a higher than desired gravity.

Asator
01-28-2010, 08:23 PM
Thanks a lot wayneb! :)

Brad Dahlhofer
01-29-2010, 08:36 PM
I recommend pitching 2 grams per gallon when using dry wine yeast. For best results, rehydrate with 1.25gram of Goferm per gram of yeast.

Fishbone
01-30-2010, 05:05 PM
I noticed an Oskaar recipe a while ago (I can't remember which one) where he pitched 4 packets of D47 in a very high gravity must...if my memory serves me correctly, I think the SG was about 1.140 in that recipe. I recently made a sweet lucuma melomel (SG was 1.136) and I pitched 4 packets of D47 similar to Oskaar's recipe (I am pretty sure Oskaar knows a thing or two about mead-making). This thing went from 1.136 to 1.024 in about 7 days. I've never had a mead ferment this fast. I used the standard staggered nutrient additions. I am wondering if this was due to the amount of yeast (4 packets), or the fact that the nutrients from the lucuma powder significantly contributed to the fermentation...or both. I made a a sack mead (not a mel) prior to this one with exactly the same SG - 1.136. I only added two packets of yeast and used the staggered nutrients additions and this batch took almost a month to get to 1.024.

...whatever the reasons...I think SOP for me from now on is to pitch 4 packets on any SG over 1.130...especially if it's D47.

Asator
01-30-2010, 08:53 PM
What about pitching more yeast after the initial pitch? For example, 3 days into the ferment and you realize that you forgot the advice of others to pitch 2 packets and you only pitched 1. I have a brew going right now that I accidentally started with 1 packet and am wondering if I should pitch another or if it is too late now. You can see my brewlog to get the specifics.
Asator's Eitr (http://www.gotmead.com/forum/forumdisplay.php?f=148)

Brad Dahlhofer
01-31-2010, 12:09 AM
I noticed an Oskaar recipe a while ago (I can't remember which one) where he pitched 4 packets of D47 in a very high gravity must...if my memory serves me correctly, I think the SG was about 1.140 in that recipe. I recently made a sweet lucuma melomel (SG was 1.136) and I pitched 4 packets of D47 similar to Oskaar's recipe (I am pretty sure Oskaar knows a thing or two about mead-making).

I regularly get a full fermentation of 1.135 meads within 7-14 days with 2g/gallon. 4g/gallon doesn't seem like it would be overpitching, so if that's what works for you. Go for it. I've just found that 2g/gal works for me.

In my case, I'm pitching 600 grams of yeast in a commercial-sized batch. I tend to not want to increase the cost if it's not really giving me a much different result.