scaling a recipe

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sashurlow

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My current setup leaves me with smaller batches if I want to all grain brew. Today I tried to fiddle around with Brewers Friend and ended up with pretty low efficiency. I'm pretty sure it revolves around the amount of water used in my mash and sparge.
Which leads to my question... how do I scale down the volume of a recipe and keep the volumes of strike vs sparge water correct?
 

rhys333

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It should all be scaled relative to the size of your batch. If you're doing half size, everything is scaled at 50%, water included. 3 gallons strike water becomes 1.5. 4 gallons sparge becomes 2.
 

RM-MN

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It should all be scaled relative to the size of your batch. If you're doing half size, everything is scaled at 50%, water included. 3 gallons strike water becomes 1.5. 4 gallons sparge becomes 2.
Not quite. Using the same or similar size kettle will get you the same boil off so if you normally would boil off a gallon with a 5 gallon batch you would also boil off a gallon with a 3 gallon batch. That throws off calculations for the strike and sparge as they cannot be just halved.
 

IslandLizard

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I use the mash + sparge water calculator at Brew 365. Quick and easy. There are others.

Efficiency has a lot to do with the grain crush. Most LHBS mills or mail ordered milled grain is fairly coarse, which impacts your efficiency. You can (ask to) run it through twice, which helps a little. If you can mill your own, tighten the gap and you'll likely see a jump in efficiency from 60-70% to 80-90%. A 2-roller mill can be had for ~$100. A knockoff Corona (corn) mill runs around $25, but you'd need to modify it a bit to get a good crush, not too fine, for a regular (non BIAB) mash.

For all grain your water quality is important. You either need to know the mineral composition of your water or, to take the guesswork out, simply use RO or distilled water. For smaller batches the latter is very doable. Then add a little brewing salts (use Bru'nwater's spreadsheet) to get your intended water profile and mash pH.

The easiest way to sparge with a "conventional" (not BIAB) mash system, using a (modified) cooler or a kettle, is batch sparging. Use that 365 calculator to get your needed water volume for the mash at your desired thickness (say, 1.33 quarts per pounds), and the rest of your water will be for the sparge. I find sparging 2x with equal amounts (half the sparge water for each), gives great efficiency.
 

crane

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My current setup leaves me with smaller batches if I want to all grain brew. Today I tried to fiddle around with Brewers Friend and ended up with pretty low efficiency. I'm pretty sure it revolves around the amount of water used in my mash and sparge.
Which leads to my question... how do I scale down the volume of a recipe and keep the volumes of strike vs sparge water correct?
It really depends on what you are scaling down from. Some random recipe you found online for a 5 gallon batch that you want to turn into a 3 gallon batch? Or a recipe you have brewed on a larger system? Or a recipe you have brewed on the same system, but now you want to do a smaller batch?

Based on your first comment it sounds like the last one is out of the equation. The first 2 are basically the same for my approach.

For specialty malts I just scale their weight by the batch size ratio. If I'm taking a 10 gallon recipe and turning it into a 5 gallon recipe then I cut their amount in half. The rationale behind this is that the flavor compounds are more easily extracted than sugars and the amount extracted does not vary much due to different mash/lautering efficiency. This assumes that you are fully draining the mash tun and have the same grain absorption rate between both systems.

Next up is your base malt. This generally does not scale the same as specialty malts because your mash/lautering efficiency is most likely not the same as the system that the original recipe was brewed on. Using your​ system's efficiency you will have to calculate the amount of base malt needed in addition to your specialty malts that will get you the same OG as the original recipe.

Now that you have your grain bill figured out you can calculate your strike water volume based on the quart per pound ratio you use on your system.

Knowing your boil off rate and boil time will tell you the pre boil volume you need. The amount of sparge water can now be calculated from pre boil volume - strike water + volume absorbed by the grain.

I use this same approach even when I am adopting a recipe of the same batch size. Most recipes are formulated around 70% efficiency whereas my system is in the upper 80s to low 90s, so I always end up scaling down the amount of base malt needed.
 

rhys333

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Not quite. Using the same or similar size kettle will get you the same boil off so if you normally would boil off a gallon with a 5 gallon batch you would also boil off a gallon with a 3 gallon batch. That throws off calculations for the strike and sparge as they cannot be just halved.
You have a point there. I'd be inclined to make boil adjustments with top-up water, post-sparge though. That way everything else including water treatment is easily scalable.
 
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sashurlow

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Thanks for the tips. The Brew365 calculator is very useful. I do believe my problems are around the volume of water added. I definitely had too much water diluting my grains too far. Two questions related to that...
Are you supposed to tip your lauter tun? I have a DIY orange 10 gallon cooler with a DIY bazooka filter on it. I was tipping it to get the last bits. That would seem to affect dead space measurement.
I've seen two references (including the original non-scaled recipe) with more strike water and less sparge water. Most other references show about 1 part strike and 2 parts sparge. How does that work?
Thanks,
To answer the question about why. I currently only have a 5 gallon kettle so I need to scale down to fit that. As far as this batch, next Friday (next day off), I'm going to use the rest of my ingredients to make a 2 gallon batch to add to my current brew. More practice...
 

IslandLizard

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Thanks for the tips. The Brew365 calculator is very useful. I do believe my problems are around the volume of water added. I definitely had too much water diluting my grains too far. Two questions related to that...
Are you supposed to tip your lauter tun? I have a DIY orange 10 gallon cooler with a DIY bazooka filter on it. I was tipping it to get the last bits. That would seem to affect dead space measurement.
I've seen two references (including the original non-scaled recipe) with more strike water and less sparge water. Most other references show about 1 part strike and 2 parts sparge. How does that work?
Thanks,
To answer the question about why. I currently only have a 5 gallon kettle so I need to scale down to fit that. As far as this batch, next Friday (next day off), I'm going to use the rest of my ingredients to make a 2 gallon batch to add to my current brew. More practice...
Sure if tipping helps to get more wort out, do it. Wort left in the deadspace is 100% loss.

Forget about volume instructions and "references," just use 365*. I typically mash in at 1.5 qts/pound, a little thinner is better than thicker, then sparge 2x with half the sparge volume each. After lautering the first runnings, I add half of the reserved sparge water (temp is not critical below 170F), stir well. let sit for a few minutes to settle, vorlauf, and collect 2nd runnings. Repeat for the second sparge.

If your kettle is small, you could use a 2nd pot (and burner) to boil down some 2nd or 3rd runnings and add to the main kettle after it has boiled off some. My 8 gallon kettle can't always comfortably hold the volume for a 5.5-6 gallon batch, so I boil a gallon or so on the side.

*There's an inconsistency in Brew 365. If you change the grain absorption number, it won't change the volume. Now the default 0.13 gallon/pound is the common brew standard and there's little need to tweak it. All other fields seem to work fine, I've tested them.
 

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I'll just chime in to add that, if you haven't done it already, it really helps to brew a few batches taking good measurements and keeping notes. Whatever calculator you use, the info out is only as good as the info you put in. Often there will be pre-set defaults that are likely not accurate for your system, which will then throw off your results. So for that deadspce, as well as boil off and other losses, you should really measure your own a few times to get accurate numbers. One thing I would caution on the Brew 365 calculator is they way they input boil off as a percentage per hr. As RM-MN pointed out above, boil off rate is more a factor of kettle size rather than how much volume is in the kettle. I prefer inputting boil off as gal per hr, but looks like that's not an option. You can still figure it out, just realize you'll need to adjust the percentage each time you change the boil size.
 

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One thing I would caution on the Brew 365 calculator is they way they input boil off as a percentage per hr. As RM-MN pointed out above, boil off rate is more a factor of kettle size rather than how much volume is in the kettle. I prefer inputting boil off as gal per hr, but looks like that's not an option. You can still figure it out, just realize you'll need to adjust the percentage each time you change the boil size.
This!
It's one thing I'll have to figure out when I do my first brew in my new home.

I moved from 1000 ft. elevation, to 7800 ft. elevation!
Water boils @ about 190-195 here, from a quick temp check in the kitchen once!
 

IslandLizard

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I'll just chime in to add that, if you haven't done it already, it really helps to brew a few batches taking good measurements and keeping notes. Whatever calculator you use, the info out is only as good as the info you put in. Often there will be pre-set defaults that are likely not accurate for your system, which will then throw off your results. So for that deadspce, as well as boil off and other losses, you should really measure your own a few times to get accurate numbers. One thing I would caution on the Brew 365 calculator is they way they input boil off as a percentage per hr. As RM-MN pointed out above, boil off rate is more a factor of kettle size rather than how much volume is in the kettle. I prefer inputting boil off as gal per hr, but looks like that's not an option. You can still figure it out, just realize you'll need to adjust the percentage each time you change the boil size.
Agreed, the Brew 365 calculator is not perfect, and it would take a small effort to fix those few shortcomings. But I haven't found anything that simple, and without convolution, that is as easy and straightforward to use.

Heck, we can write our own calculator (e.g., Excel, Google Sheets) anyway we want, it's not that hard. Even a web version of it.

On the notion of what you put in is what you get out, one thing that needs some serious attention is the heat loss suffered while you're mashing in with the mash vessel wide open, exposed to the ambient air. There is no calculator out there that let's you enter some target value for it.

For example, my strike temp needs to be 4-6°F higher than calculated (with any calculator) to come out at the target mash temp. That's indoors! I usually aim at 6F over, and stir a little longer if needed, until it's 1 degree above target. By the time I cover the mash with aluminum foil and close the cooler, it stabilizes right where I want it to be.
 
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sashurlow

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Because I'm pretty sure my problems were with too much water, just how much of a boil are you supposed to have. A rolling boil? A simmering boil? Heck, taking the lid off vs leaving it on affects how much gets evaporated off. I have put numbers in to Brewer's Friend and 365 and am choosing the lesser volume one due to my first attempt. Practice... The nice thing is that even practice brews leave you with beer.
Since we are on the topic... With so many variables in play, how do you get any recipe to come out the same as the person who created it?
 

IslandLizard

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Because I'm pretty sure my problems were with too much water, just how much of a boil are you supposed to have. A rolling boil? A simmering boil? Heck, taking the lid off vs leaving it on affects how much gets evaporated off. I have put numbers in to Brewer's Friend and 365 and am choosing the lesser volume one due to my first attempt. Practice... The nice thing is that even practice brews leave you with beer.
Since we are on the topic... With so many variables in play, how do you get any recipe to come out the same as the person who created it?
A gentle rolling boil used to be the norm, but there have been brewers that say a mere simmer (ripples on the surface) is enough. Some even claim leaving the lid on made no difference in retained DMS or boil off volume compared to leaving it off (Brulosopher.com).

You should know the boil off on your system, and use that number. If your calculator uses a percentage, then convert it to that. A gallon an hour is average. On my stovetop it was 3/4 gallon an hour, I barely had a simmer unless I left the lid on half way. That worked fine.
Then again, you'd be off only 1 or 2 quarts, not a big deal. Correct better next time.

Brewing a recipe the same as the guy who wrote it? Fat chance! He couldn't even do it.

Some recipes are surely written better than others. You can get close as long as you know the grain percentages, OG, and AAUs (or IBUs) of each of the hop additions. Enter those into BF or Beersmith, then tweak to your equipment specs and efficiencies to get the same or similar numbers. But you still don't know how he fermented, the quality of his yeast, his water, and all those other factors that make each brew unique.

After all, why would you want his, your version maybe better.

It's very difficult on homebrew scale to even brew the same recipe exactly the same each time. Our variations are much larger because we're dealing with such small volumes (relatively).
 
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