What is meant by batch size?

When recipes refer to "batch size" or "yield", is this your post-boil volume that is going into the fermenter, or is this what you are likely to get out of your fermenter after removing it from the trub? If it is the former, then a 5 gallon batch seems to rarely produce a true 5 gallons.

I have gotten fairly proficient at calculating my volume losses to the mash tun, grain, boil, etc., but wanted to be sure my final target volume is correct.

Thanks, in advance!

Batch size is the gross amount into the fermenter, post-boil.

You are correct that your final yield will always be smaller than this number, thanks to trub loss and the like. I always scale my recipes up to 5.25 or 5.5 gallon batches now to account for this.

These are the numbers that are usually given, yes. I suspect that the exact number varies. Given my system, my habits, etc. For a nominal 5 gallon batch, I usually end up with 51 or 52 12 oz. bottles, i.e., a tad short. It works for me.

Thanks for the fast responses. Seems like both of you encounter an approximate 1 quart loss.

Homebrewdad, I like your suggestion of scaling up to offset this. My brew app has a scale feature, so I may put it to work for me.

Thanks again.

You're quite welcome.

I personally aim for 48 bottles; my last batch was 49.5 (and I only had 48 cleaned and ready), so I just pulled a glass from the bucket. Yay for warm, flat (but tasty) beer! I find that 5.25 - 5.5 gallons gets that for me. Different yeasts/recipes end up with different amounts of beer-sucking trub.

homebrewdad said:

Batch size is the gross amount into the fermenter, post-boil.

You are correct that your final yield will always be smaller than this number, thanks to trub loss and the like. I always scale my recipes up to 5.25 or 5.5 gallon batches now to account for this.

Click to expand...

5.5 for a 5 gallon batch
11 for a 10 gallon batch
I like to have plenty of wort so no trub or hops go into my fermenter.
I usually lose a quart or so. I like to end up with a small layer of nice clean yeast at the bottom.

I leave a little less than a quart behind in primary. When I bottled I did 5.5 into the fermenter and would usually get two cases and a six pack. I'd use the six pack as testers. Now I keg I shoot for 5.2 into the fermenter to get a full keg. If I use a secondary I need to start closer to 5.5. Some start at 6 and leave more behind.

Regardless if I need 10.5 gallons for 10 or 5.5 for 5 in the recipe I still refer to it at a 10 or 5 gallon batch. The finished beer is really all that counts.

I always calculate a 6 gallon batch, post boil. That way I put 5.5 into the fermenter and then 5 in the keg (or bottle). I'm always guaranteed a true "5 gallon batch".

oh, he said bAtch size....miss tell.

Sorry for the delayed response. Thanks again for all the additional input. I think I have finally fine-tuned my volume calculations. Scaling up has helped a lot.

I've heard the term knockout volume as well. I believe this is the volume in the kettle before draining to the fermenter correct?

If I put any more than 5 gals in my 6 gal Better Bottle fermenter then it will blow over so I stick to 5 gal batches which usually yields about 42-44/12 oz bottles.