[vinnieb]

Greetings all!  This is my first post, and I can't seem to find detailed info on yeast amounts for a 1 gallon batch of Ale.  I use Beersmith 2 and took a 5 gallon SMASH  recipe of mine and scaled it to a 1 gallon batch.  I adjusted all the ingredients except one...very important one, the yeast.  It totally slipped my mind and didn't dawn on me until I was ready to pitch it.  I was using Wyest slap pack for a 5 gallon brew.  After it was ready to pitch, I poured it into a measuring cup and tried to eye ball 1/5th of a half a cup.  I don't think it was enough.  My question are:  1) Could I have just used the entire pack?  2) Is there a preferred way to gauge the amount of yeast needed for 1 gallon brews?  3)If fermentation does take in a few days can I add a fuel tablet or can I add half a package of dry yeast.  I used wyest American Ale, I have an 11g US-Safle in the freezer.

Any help will be appreciated!

[klickitat jim]

What was your OG?

If it was under 1.060 then you pitched a little over twice as much yeast as you needed if you pitch a whole fresh smack pack.

[vinnieb]

The OG is 1.43.  I just came from checking the carboy.  It appears fermentation started.  Its not aggressive or slow but looks to be normal. I have a blow off set up and the carboy is set into my 5 gallon primary.  I am assuming maybe its better to use the 11g dry yeast instead of the slap packs?

[repo]

In beersmith, click the tools icon, then select yeast starter. From there it will allow you to enter the wort size and gravity and then calculate how much yeast is recommended. The production date of the yeast also factors in. There are a few other yeast calcultors out there.
mrmalty.com
yeastccal.com
brewersfriend.com

It is possible you could have used/needed the whole pack.

I would use dry yeast by weight, or harvested yeast by ml to pitch to 1 gallon. Any of those calcs will tell you how much for a given size/gravity.

Yes you can pitch more yeast if fermentation doesn't begin, but you probably won't need to.

[vinnieb]

Thanks! Ran the numbers on Beersmith, I may have under pitched.  I'll check it again in a day, if not much is going on, I'll throw in the 11g of Dry. 

At least I know what to do on Sunday when I make another 1 gallon batch.

[bboy9000]

Was the OG 1.43 or 1.043?

[morticaixavier]

Thanks! Ran the numbers on Beersmith, I may have under pitched.  I'll check it again in a day, if not much is going on, I'll throw in the 11g of Dry. 

At least I know what to do on Sunday when I make another 1 gallon batch.

11 grams of dry yeast is WAY WAY WAY too much yeast for 1 gallon of beer. at 1.043 what you pitched is fine. you could have pitched 1/3 of the smack pack and been fine too.

Check out mr malty or yeast calc. either one allows you to enter a gravity and volume and gives you the starter size, and the correct amount of yeast in cells or packs and fractions of packs.

Mr Malty says .5 packs if the pack was 6 weeks old.

A smack pack has ~100 billion cells in it fresh. My Malty calculates you need about 30 billion for your 1 gallon batch. Say you lose ~25% of the cells per month, if the pack was 1 month old you would be fine with  half, if it were 2 months old (past it's use by date at this point) you would be fine with most of a pack (or the whole pack) at 3 months old you would want to use the whole pack.

for dry yeast, you would want to use about 2 grams for the 1 gallon batch.

**EDITED** for correction of 1 to 11 in the first line of my response

[vinnieb]

Wow, this is all an eye opener.  I just learned that I have been using my yeast wrong.  Which is most likely the reason I scored 26.8 on the Beer Revival here in NY.  I usually keep the liquid yeast in the fridge for a month or two before I use it, and since I make mostly 5 gallon batches, I assumed it was straight forward process.  My 3 gal batches have been off in flavor and vigor....I've been doing it all wrong. 

I got mrmalty app now, and been fixing my numbers in beersmith profiles. 

Thanks again guys!