Author Topic: scaling amounts of 5G recipes to 1G BIAB recipes  (Read 502 times)

Offline John Murphy III

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scaling amounts of 5G recipes to 1G BIAB recipes
« on: April 28, 2021, 11:30:04 pm »
Hi All,
I am still new at brewing, 15 extract beers into it.  I want to try BIAB, but 1 gallon batches so I can play around with flavors and such.  Does anyone know how to scale down a 5G recipe to a 1G recipe...or am I being stupid and it's as simple as dividing everything by 5.  I only ask because I am a chef and straight division or addition (making recipe bigger) doesn't always work with all ingredients.   Thank you in advance.
Cheers!
john

Offline BrewBama

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Re: scaling amounts of 5G recipes to 1G BIAB recipes
« Reply #1 on: April 29, 2021, 12:19:47 am »
Hey John. I do this all the time in BeerSmith. 

I would convert the 5 gal extract batch to grain first, then scale from 5 gal grain to 1 gal grain.

Your instincts have served you well because you could get a different efficiency from a 5 gal grain batch and a 1 gal grain batch.

For example, I plan 75% for my HERMS Batch Sparge 5 gal batches but only plan 67% in my 2 gal no sparge batches. If you don’t know your efficiency you’re going to have to wing it until you get an idea of how efficient your processes are.

I’d start with 2-2.5 lbs of crushed grain in a cpl gals of brewhaus liquor as a guess. If it’s high gravity you can add brewhaus liquor to thin it out and if it’s low you can add some sugar, honey, molasses, extract, etc to dial it in.
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Offline majorvices

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Re: scaling amounts of 5G recipes to 1G BIAB recipes
« Reply #2 on: April 29, 2021, 01:28:46 am »
I get lower efficiency on my 1 gallon batches for a few different reasons. You might or might not depending on your set up. Losses tend to get magnified when you get around 1 gallon for a few different reasons.

Offline John Murphy III

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Re: scaling amounts of 5G recipes to 1G BIAB recipes
« Reply #3 on: April 29, 2021, 06:34:42 pm »
Thank you guys for your help!! 

Offline Drewch

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Re: scaling amounts of 5G recipes to 1G BIAB recipes
« Reply #4 on: April 30, 2021, 12:40:46 am »
Hi All,
I am still new at brewing, 15 extract beers into it.  I want to try BIAB, but 1 gallon batches so I can play around with flavors and such.  Does anyone know how to scale down a 5G recipe to a 1G recipe...or am I being stupid and it's as simple as dividing everything by 5.  I only ask because I am a chef and straight division or addition (making recipe bigger) doesn't always work with all ingredients.   Thank you in advance.
Cheers!
john

I do this all the time. My standard batch size is 4L. Start with the scaling function in your favorite brewing app and adjust from there. You'll have to do a few batches to dial in the losses (boil off, grain absorption, etc) of your particular setup.

Edit: Oh, and mash efficiency, too. I started with assuming 65% and adjusted based on actuals. I usually got about 80%, but as long as it's consistent, you can adjust the recipe to hit the OG you're aiming for.
« Last Edit: April 30, 2021, 12:45:53 am by Drewch »
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Offline reverseapachemaster

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Re: scaling amounts of 5G recipes to 1G BIAB recipes
« Reply #5 on: May 01, 2021, 03:46:35 pm »
A lot of people scale linearly and while that is ok IMO you need to consider water volumes and how those are affected at each volume. In many years of brewing small batches and scaling down larger recipes I've never seen a real difference scaling hops, yeast and grain linearly. I have scaled commercial recipes to five gallons and less and in those cases both mash and hop use efficiencies deserve more attention.

If you brew multiple batch sizes with the same equipment then you need to account for dead space in the mash/sparge/racking and boil off generally as fixed volumes. If you lose a pint of liquid along the way in a five gallon batch then you're probably going to lose the same amount on a one gallon batch. You can't divide your losses by five. Boiloff can also change your final volume. If you boil a small amount of wort with a lot of surface area and/or with the same amount of heat you would apply to a five gallon batch you will likely lose more volume to boiloff. So you should plan on a couple pilot batches to figure out how much heat to apply to a smaller batch, whether it makes sense to use a smaller kettle and how much boiloff you expect to have. If you use brewing software you'll want to create a separate equipment profile for these smaller batches.
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Offline erockrph

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Re: scaling amounts of 5G recipes to 1G BIAB recipes
« Reply #6 on: May 01, 2021, 05:19:46 pm »
A lot of people scale linearly and while that is ok IMO you need to consider water volumes and how those are affected at each volume. In many years of brewing small batches and scaling down larger recipes I've never seen a real difference scaling hops, yeast and grain linearly. I have scaled commercial recipes to five gallons and less and in those cases both mash and hop use efficiencies deserve more attention.

If you brew multiple batch sizes with the same equipment then you need to account for dead space in the mash/sparge/racking and boil off generally as fixed volumes. If you lose a pint of liquid along the way in a five gallon batch then you're probably going to lose the same amount on a one gallon batch. You can't divide your losses by five. Boiloff can also change your final volume. If you boil a small amount of wort with a lot of surface area and/or with the same amount of heat you would apply to a five gallon batch you will likely lose more volume to boiloff. So you should plan on a couple pilot batches to figure out how much heat to apply to a smaller batch, whether it makes sense to use a smaller kettle and how much boiloff you expect to have. If you use brewing software you'll want to create a separate equipment profile for these smaller batches.

When I was brewing on the stovetop, I saw a noticeable increase in boiloff rate when I brewed smaller batches. This is because my full size batches were about as big as my burner could bring to a bare boil. Smaller batches would boil off more vigorously. I would plan on losing at least as much as you would on a large batch, but it will likely be even more. I ended up reducing my boil to 45 minutes on these batches to account for this, but you could just as easily adjust your preboil volume once you have a few batches under your belt.
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Offline Drewch

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Re: scaling amounts of 5G recipes to 1G BIAB recipes
« Reply #7 on: May 06, 2021, 03:33:22 pm »
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Offline majorvices

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Re: scaling amounts of 5G recipes to 1G BIAB recipes
« Reply #8 on: May 06, 2021, 04:28:12 pm »
The biggest problem I have found with 1 gallon batches is that the losses are magnified greatly. You figure that if you realy get a final 1 gallon volume in your fermenter you will essentially get a little over 12.5 twelve ounce beers. But if you have a lot of hop sediment or trub in your kettle that doesn't manage to settle out all the way you can lose a lot of beer. I have been going so far as to let the beer settle overnight and then racking off the compacted trub so as to get as much wort as possible. Likewise, when racking off the yeast any mistakes that are made can cause you to lose a good portion of your product. Leave behind 1 or 2 pints behind on a 5 gallon batch you hardly notice it. Leave 1-2 pints behind on a 1 gallon batch and you just lose maybe 20% of your batch. I'm talking about weird stuff that happens like losing focus and breaking the siphon and stirring up the yeast or accidentally aerating the batch because you didn't have the bucket or siphonless carboy tilted properly.

The way my 1 gallon batch mashtun is designed I have found I have to sparge longer to get extract the most from the runnings which then means I usually have to boil longer to increase the evaporation. Or I can just add a little extra malt and lower my efficiency to 65%.

Every brewer is going to be different obviously. Those are the issues I have stumbled across.
« Last Edit: May 06, 2021, 04:29:46 pm by majorvices »

Offline Drewch

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Re: scaling amounts of 5G recipes to 1G BIAB recipes
« Reply #9 on: May 06, 2021, 08:58:28 pm »
The biggest problem I have found with 1 gallon batches is that the losses are magnified greatly.

My experience is that this definitely true.  Trub and fermenter losses in a 4-L batch will be higher as a percentage of the total batch than with a 20-L batch. I figure on leaving 25% in the fermenter and only count on getting 8 12oz/33cl bottles out of a 4-L batch.

But I still stand by it as a way to experiment with more recipes faster and cheaper than traditional 5-gallon batches.
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Offline majorvices

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Re: scaling amounts of 5G recipes to 1G BIAB recipes
« Reply #10 on: May 07, 2021, 12:05:50 am »
Absolutely a great way to experiment. Right now I'm only brewing "1 gallon" batches. 5 liter to be more precise. I probably get a little over a gallon finished product. I have significantly cut back on my drinking but I still enjoy brewing so this is the best of both worlds. I'l even doing decoction mashes in my microwave. Loads of fun.

Offline BrewBama

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Re: scaling amounts of 5G recipes to 1G BIAB recipes
« Reply #11 on: May 07, 2021, 12:46:29 am »
... a way to experiment with more recipes faster and cheaper than traditional 5-gallon batches.

+1
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