Scaling a recipe?

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Dude

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If I wanted scale a recipe from 5 gallons to 10 gallons, do you just double everything (hops too) and it is good? I know it sounds like a stupid question (obvious), but I want to make sure.

I'm brewing 10 gallons of Lake Walk real soon. Only problem is it has to wait for a new mashtun, or until SwAMi gets back. Hurry up bee-yotch.
 
Does promash scale everything linearly? I just did a batch and used promash to scale it down and it worked out fine. Just click "lock ingredients to batch size" and change the batch (I'm sure you know.)

Brewpastor should know for sure, he does the biggest batches around here, I think.
 
I don't see why it should not be liner (at least for the grains). I'd do the same for the hops since I wouldn't know how the utilization is affected by the increased boil size. None of the tables that we use for utilisation account for different boil sizes anyway.

Not as dumb of a question as it sounds, Dude.

Kai
 
i'd just double the ingredients... but i'm not one for fancy equations, fractions and the like...

this is about as complicated as i can get: 2/5=x/10. where x would equal 4, and i'm not even sure i can remember the necisary algebra to solve the equation.... ;)
 
I agree--double everything.

Hops utilization should be the same. As someone mentioned, that is a function of SG of the boil, not volume.

The one thing you might want to adjust is evaporation percentage. I think you can assume you'll get a somewhat less vigorous boil with twice as much wort.

So if you usually boil 6.5 gallons to get a 5 gallon batch, you might only need to boil 11.5 or 12 gallons to get a 10 gallon batch.

But I'm just WAGing on these figures.
 
I think hop utilization is more dependent on the gravity of the wort as opposed to boil volume.

: Hops and IBUs: In figuring your IBUs, does batch size make a difference (say 10-gal versus 10-bbl)? The formula I use is from the Zymurgy hops special issue (1):

%Ux%AXWg
IBU= --------- x 1000
VLx(1+GA)

where U = utilization, A = a-acid content, Wgr = weight in grams, VL = volume in liters, and GA = gravity adjustment. The V above: is it the starting volume or the final volume?
DM: The short answer to your first question is, yes, batch size makes a difference. Small-scale brewers often find that moving to a different batch size alters their hop utilization. And to answer your second question: Utilization usually is calculated based on the volume of wort in the kettle at the end of the boil. This practice makes it easier to compare figures from different breweries because losses at later stages in the process can vary tremendously.
I sense another question lurking behind your first, though: "If batch size makes a difference, how does one compensate for it? Is there another term that can be inserted into the formula?" The answer to that, alas, is no.
Strictly speaking, an IBU is one part per million of isohumulone. It is a quantity that must be measured directly in the finished beer. All of the formulas published in the home brewing literature - and you have no doubt noticed that there are several, and that they give varied results - at best will allow you to make a rough estimate of a beer's IBUs.
Remember that all of these formulas include a term for utilization percentage. In some formulas, a fixed percentage is built in; in others, you must supply it. Either way, it's there. The only way to plug an accurate number into that slot is to measure the actual IBUs in a laboratory. If you can do that with several test brews, you can then predict the IBUs of future batches - assuming of course that you do not change your brewing techniques or equipment.
The problem is that batch size is far from the only variable that can affect utilization. Some other variables include the following:

Form of hops. Pellets give better utilization than whole cones. Sometimes a factor is included to account for this in the formulas.
Time of hop boil. All formulas include a factor to compensate for this.
Gravity of the wort. Some formulas include a factor for this.
Agitation in the boil. Kettle configuration and material, placement of the heat source, and numerous other factors influence how much rolling action you get during the boil. There is no way to figure in a factor for this because it is unknown to the formula writer and is difficult to measure in any case.
Time of hot stand after boil and before cooling. This again is unknown to the formula writer.
Agitation after the boil. If the wort is whirlpooled with the hops, even the finish hops will yield a respectable percentage of their bitterness. Again, there is no way to figure in this factor.
Losses during fermentation. Yeast cells adsorb hop bitterness, as a simple taste test proves. The degree of adsorption depends on a multitude of factors, not the least of which is the amount of cell growth.
To give some idea of how important these unknown and unaccountable factors can be, let me cite two beers we brew at The Saint Louis Brewery: our wheat ale and oatmeal stout. Both were analyzed by friends with access to a large and well-equipped brewing laboratory. Both beers are brewed using pelletized hops, and both are fermented using the same yeast strain, pitching rate, and method. For the oatmeal stout, we add all the hops 45 min before the end of the boil. Wort gravity is 1.056. Our hop utilization is 31.5%. For the wheat ale, we add 50% of the hops (by a-acid) 30 min before the end of the boil and the remainder at the finish. Wort gravity is 1.037. Our hop utilization is 26.8%.
You may ask, what in the world is going on here? Other things being equal, you would expect a little better utilization in the wheat ale because of the lower gravity, but in no way could that make up for the difference in boil times. Remember, by the article you are following, we should be getting only about 5% utilization from our finish hops.
The answer (in part) is that our kettle also is a whirlpool, and we whirlpool the wort for 20 min and then let it settle for another 10-15 min before knocking out. Obviously, 30 min of agitation at near-boiling is almost as effective as boiling for a similar period.
OK, this is a gross example, and you might argue that you could still use the formula if you simply include the 30-min whirlpool period in the total boil time. But that still will not get you anywhere near an accurate estimate. Figuring the finish hops as a 30-min boil and the first addition as 1 h, we should (again by the article you are following) get an average utilization of 30 + 15.3/2 = 22.7% - significantly below the actual figure.
Every published formula I have seen for estimating IBUs has more than an outside chance of giving you a grossly inaccurate estimate of the bitterness in your finished beer. The brewing process simply contains too many variables, and some of them are nearly impossible to quantify. Whenever a brewer tells me, "This beer has so many IBUs," I have to ask in turn, "What lab did the measurement?" There is a real need for a good, reasonably priced lab service that would measure bitterness for small-scale brewers.
In any case, I see no advantage in publishing recipes that require working backwards from an IBU figure through a complex formula to derive a hop rate. The simple old AAU (a-acid unit) or HBU (homebrew bitterness unit) system is just as likely to get you in the ballpark. Furthermore, brewing encompasses art as well as science, and setting bitterness falls on the art side of the process. You have to go by taste. All the calculations are only a means to let you use your knowledge and experience to get a beer that tastes right - the right amount of bitterness, in this case - in as few trials as possible, and then to repeat or fine-tune the flavor of that beer.
I hope it doesn't sound like old technical Dave is getting arty and muddle-headed. Flavor is the reason we brew and drink beer. Even the biggest and most technically proficient brewers in the world rely on taste panels as the ultimate analytical instrument. Numbers do not tell the whole story; they are only a means to an end. So if we cannot fix a recipe entirely by formulas, it's not the end of the world. We can still brew great beer.
Found this apparently it isn't as simple as just Gravity or volume
 
Dude said:
If I wanted scale a recipe from 5 gallons to 10 gallons, do you just double everything (hops too) and it is good?
Not to get picky here, but you should lose the same amount to evaporation in a 10 gallon batch as you would in a five, and your kettle loss would be the same, so really you wouldn't just double it. With my system I'd need to multiply by 1.9, but since you've got that fancy vacuum gizmo, it would probably be more like 1.95 for you (since you have no loss in the kettle).
 
might be something that has already been said, I didn't realize how much had already been posted:

cweston said:
Hops utilization should be the same. As someone mentioned, that is a function of SG of the boil, not volume.

According to some sources, hop utilization is also affected by the geometry of the boiling wort. But I don't think that there is a significant affect that we actually have to worry about this and even if, i have yet to see some quantitative data.

I just read the great article that Budbo posted:

Every published formula I have seen for estimating IBUs has more than an outside chance of giving you a grossly inaccurate estimate of the bitterness in your finished beer. The brewing process simply contains too many variables, and some of them are nearly impossible to quantify. Whenever a brewer tells me, "This beer has so many IBUs," I have to ask in turn, "What lab did the measurement?" There is a real need for a good, reasonably priced lab service that would measure bitterness for small-scale brewers.

If you think your beer tastes to bitter or to mellow than it should, feel free to adjust the hops next time you brew this even if it looks like you are changing the IBUs requested by the recipe.

Kai
 
El Pistolero said:
Not to get picky here, but you should lose the same amount to evaporation in a 10 gallon batch as you would in a five, and your kettle loss would be the same, so really you wouldn't just double it. With my system I'd need to multiply by 1.9, but since you've got that fancy vacuum gizmo, it would probably be more like 1.95 for you (since you have no loss in the kettle).
Is this true? Assuming use of the exact same kettle, I would have guessed that you'd have a greater percentage of evaporation from a 10g boil than a 5g boil due to there being less headspace in the 10g boil and hence less condensation returning to the boil.

I'm pretty sure I need a HB.
 
Baron von BeeGee said:
hence less condensation returning to the boil.

Condensation returning to the boil? Is there a lid on?

I'd say that the opposite is true if the evaporation is atually a function of the wort surface during the boil (I'm not sure how much that is true). In this case there should be the same total loss in a 10 gal and a 5 gal boil. This is less percent of loss in the larger boil.

Kai
 
Kaiser said:
Condensation returning to the boil? Is there a lid on?

I'd say that the opposite is true if the evaporation is atually a function of the wort surface during the boil (I'm not sure how much that is true). In this case there should be the same total loss in a 10 gal and a 5 gal boil. This is less percent of loss in the larger boil.

Kai
I'm thinking of the converted kegs when we talk about larger boils. With a straight sided pot I don't know if it would be as much of an effect. But definitely with the domed kegs the evaporated wort will have more time to cool before reaching the top for a 5g boil than a 10g and may then condense on the curved portion of the keg. I imagine this effect is still applicable in a straight sided pot, but to a much lower extent. Actually, I'm pretty sure of that if I imagine an infinitely tall pot where all evaporated wort would eventually condense and return.

I do agree that the surface evaporation measured right at the surface of the boil should be the same in both cases given that the surface area is the same for both levels of wort.
 
Baron von BeeGee said:
I imagine this effect is still applicable in a straight sided pot, but to a much lower extent. Actually, I'm pretty sure of that if I imagine an infinitely tall pot where all evaporated wort would eventually condense and return.

That's a good point, I didn't think about this.

Kai
 
I dunno about Promash, but Beersmith will scale recipes for you. I know it doesn't help you, you have Promash...................
 
ablrbrau said:
I dunno about Promash, but Beersmith will scale recipes for you. I know it doesn't help you, you have Promash...................

Can you do an experiment for me and see if it doubles everything exactly?



OMG...I cannot believe the can of worms I opened with this thread....Should I make it go away? :p
 
Dude said:
OMG...I cannot believe the can of worms I opened with this thread....Should I make it go away? :p

No, because then I would have to do actual work and can't work on getting to 1000 posts by the end of today ;)

Kai
 
Dude said:
Can you do an experiment for me and see if it doubles everything exactly?

BeerSmith seems to double everything exactly. This is what I expected since there is no quantative data or formula available to do anything more sophisticated. Despite all the discussion we had about this, I'd do exactly the same.

Kai
 
Kaiser said:
BeerSmith seems to double everything exactly. This is what I expected since there is no quantative data or formula available to do anything more sophisticated. Despite all the discussion we had about this, I'd do exactly the same.

Kai

Rog. Thanks.

So essentially, RDWAHB, Dude. :p ;) :mug:
 
Well I don't know if its strictly 'correct' but I can tell you for sure that in ProMash if you check 'lock ingredients to batch size' and then double the boil volume, it will exactly double all ingredients, grain and hops.
 
I migrated from 5 to 10 gallon batches in January of this year, and so far here is what I know. The malt scale is mostly linear according to my math. I say this due to the fact that I due all my calculations by hand, i.e., no software involved other then a few formula's on an excel spreadsheet. BTW I really suck at math. :(
There are the two major issues I have encountered (as if there could be more). Gravity and Volume. It took me four batches to hit my volume, and I have still yet to come within an accetaple range of meeting the gravity that I am looking to achieve.

I finally hit my volume with the 10 gallon version of the California Common that the Pastor provided. I missed the gravity by a mile. The range was 1.048 to 1.054 I came up with 1.042.

In order to correct this I'm speculating that I may need to lauter for at least 40-60 minutes as well as adjust the rate of evaporation accordingly to increase efficiency.:ban: I'll start with those basic tasks and see if my efficiency improves. In the event it doesn't, I'll be back here looking for some insight. :drunk:

I started with 13.25 gallons and ended with ~10ish gallons. I lost 2 gallons in the mash, and 1.25 in the boil.

Then there is your yeast culture. You'll need to be growing some of that up too. :fro:
 
glibbidy said:
It took me four batches to hit my volume, and I have still yet to come within an accetaple range of meeting the gravity that I am looking to achieve.

If you keep missing your gravity and volume, do what I do:

- when you are done lautering, measure volume and gravity. Now you can determine the after boil volume based on the OG. You can also determine a conservative boil time in case you don't expect to boil off the difference in 90 or 60 min
- start boiling
- when 15 min are left, turn the flame off to stop the boiling and see where you are at with the volume. Now put your immersion chiller in and resume the boil
- claculate the amount that will be boiled off in the remaining 15 min and start boiling the amount of water you need to add to hit your calculated after-boil (cast-out) volume. Add that water as soon as it boils.
- now you should hit your gravity dead on, everytime.

Kai
 
Kaiser said:
If you keep missing your gravity and volume, do what I do:

- when you are done lautering, measure volume and gravity. Now you can determine the after boil volume based on the OG. You can also determine a conservative boil time in case you don't expect to boil off the difference in 90 or 60 min
- start boiling
- when 15 min are left, turn the flame off to stop the boiling and see where you are at with the volume. Now put your immersion chiller in and resume the boil
- claculate the amount that will be boiled off in the remaining 15 min and start boiling the amount of water you need to add to hit your calculated after-boil (cast-out) volume. Add that water as soon as it boils.
- now you should hit your gravity dead on, everytime.

Kai
I noticed ProMash in the water needed window calculates 4% reduction when the wort is cooled. Do we also need to do this when measuring pre-boil volume?
 
RichBrewer said:
I noticed ProMash in the water needed window calculates 4% reduction when the wort is cooled. Do we also need to do this when measuring pre-boil volume?

That is a good question, and I have been asking this myself lately. But since pre and post boil volumes are measured at almost the same temp, there shouldn't be a need for this. To be exact, you would only need to scale the additional water needed based on temperature but those 4% won't change it much.

Kai
 
What's it like up there? Unseasonably hot here...usually in the 80's lately. Finally got a decent batch of rain today (we're ~8" below normal, I believe). Between soccer on Sundays, yardwork, and a trip to the beach at Easter my gent is a bronze god!
 
Baron von BeeGee said:
Between soccer on Sundays, yardwork, and a trip to the beach at Easter my gent is a bronze god!

LOL

We had a couple nice days last week, in the mid 80s in your out-dated system, then it snowed on Saturday... So my gent is not really a bronze god, more like a ruddy barbarian.
 
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