Scaled down recipe - reduced efficiency

[skyblue67]

I usually brew 23lt batches using BIAB but recently I brewed a small batch which hasn't turned out entirely as planned. Mainly due to poor efficiency, I usually get about 75%, this time only 61%. Is this typical of brewing on smaller scale?
The recipe is here https://www.brewersfriend.com/homebrew/recipe/edit/534258

The sugar addition has actually gone into the fermenter after 2 days. I did this to bump up the abv, although maybe I should have researched this option beforehand but I guess it should be ok.

I'm quite keen to brew more small scale batches but should I allow for poor efficiency?

 

[Nosybear]

I usually brew 23lt batches using BIAB but recently I brewed a small batch which hasn't turned out entirely as planned. Mainly due to poor efficiency, I usually get about 75%, this time only 61%. Is this typical of brewing on smaller scale?
The recipe is here https://www.brewersfriend.com/homebrew/recipe/edit/534258

The sugar addition has actually gone into the fermenter after 2 days. I did this to bump up the abv, although maybe I should have researched this option beforehand but I guess it should be ok.

I'm quite keen to brew more small scale batches but should I allow for poor efficiency?

Short answer, yes. For a longer answer, you'll have to share the recipe.

 

[Ozarks Mountain Brewery]

in recipe edit go to recipe tools and share, just check all 3 and copy that link

 

[J A]

My efficiency seems to drop with smaller batches and smaller malt bills. For me I think it has to do with grain column in the sparges...With a "flatter" grain bed there's just less resistance to the draining water so it's hard to slow it down and take advantage of rinsing the sugars out of the grain. With BIAB there's less involved with the sparge I'd look at your method and see if you can eke a little more out of your malt. Maybe change the ratio of mash thickness/strike volume to sparge volume.

 

[Nosybear]

Smaller batches are less efficient - but I wouldn't think you'd lose 14 percent! Of course, until we can see the recipe, I have no idea how far he scaled it down. I do a lot of 2.5 gallon batches - about 11 liters - and don't get that kind of efficiency drop.

I've had weird results for efficiency in the Recipe Builder when I'm adding sugars and even stranger results when doing a small batch. I'm wondering if the efficiency drop is an artifact of how the recipe was built? If the sugars are in the fermentables list and not marked late addition, the predicted OG would be based on the grain and the sugar. The actual wort would not have the sugar, so the hydrometer would give a low gravity reading (the predicted OG minus the sugar's contribution), resulting in a low efficiency.

 

[J A]

That^^^
I scratch my head every time I do a fermenter-addition batch until I remember to factor out the sugar that's going in later. Did it just the other evening and couldn't for the life of me figure out why my post-boil wort was .049 rather than the .056 or so that the recipe said it should be.

 

[Ozarks Mountain Brewery]

one thing to realize the starting and ending gravity good be off and you might not be as lop sided as you think

and Ive had yest that over performed and some under buy a lot so that could play into it too, not every batch is absolute

 

[skyblue67]

Thanks for all the replies. I've still got beer fermenting, maybe it won't turn out quite as planned but so long as it's drinkable I don't mind.

 

[BoomerBrian]

Hmm....Never thought about efficiency being lower due to the batch being smaller. I do 3 gallon BIAB and don't have great efficiency 65% but it is consistent and that is all that matters.

 

[Nosybear]

I get around 80% in my 5-gallon batches, around 75% in my 2.5 gallon batches. Breweries expect around 85% doing multiple barrels at once.

 

[chub1]

I seem to get around 70% with my 5/6 litre BIAB batches which i am happy with

 

[GFHomebrew]

I average around 80% efficiency on 21 lt batch with thin 6lt/1kg mash and sparge with 5 lt. I find that around the 4-5kg grist mark is my sweet spot for best efficiency using that system. Once i head up abive into the 6kg and beyond mash i find my efficiency drops to 65 ish%. Thats on the few high gravity beers ive done...

 

[KC]

I usually brew 23lt batches

If you used the same equipment for the smaller batch, your normal losses in hoses, false bottoms, etc. will all be the same and that ends up as a higher % loss of a smaller volume; lower brewhouse efficiency. Likewise, added tun head space makes temperature control less stable and that can throw off your rest targets. Rounding and measurement errors in volume and weight also have a greater impact on smaller batches, so calculations contribute to bad numbers.

Small batches aren't inherently prone to low conversion efficiency. If process and equipment aren't optimized for it then results will be off.

 

[skyblue67]

If you used the same equipment for the smaller batch, your normal losses in hoses, false bottoms, etc. will all be the same and that ends up as a higher % loss of a smaller volume; lower brewhouse efficiency. Likewise, added tun head space makes temperature control less stable and that can throw off your rest targets. Rounding and measurement errors in volume and weight also have a greater impact on smaller batches, so calculations contribute to bad numbers.

Small batches aren't inherently prone to low conversion efficiency. If process and equipment aren't optimized for it then results will be off.

I used a smaller pan and brewbag for this batch