Author Topic: Hops and pre boil volume  (Read 9859 times)

Offline brewprint

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Hops and pre boil volume
« on: February 26, 2017, 11:21:55 AM »
I've noticed that my preboil volume never, ever changes.

No matter how many hops I put in there, it remains the same.

How is this possible? Let's say for example; I have a recipe with a 1lb addition at 5 minutes left in the boil. Wouldn't that require me to have a larger pre-boil volume?

What am I missing here?

Offline Oginme

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Re: Hops and pre boil volume
« Reply #1 on: February 26, 2017, 12:55:57 PM »
Beersmith does not factor in water absorption of the hops.  Typically, it would be reflected in the 'loss to trub and chiller' section, but I find that varies from recipe to recipe.

What I do for a 10 liter batch is plan on 10 liters into the fermenter and 1 liter loss to trub and hops.  This covers my loss for heavily hop loaded recipes easily enough and I can always overshoot the actual volume to the fermenter on those recipes which have minimal hop loading.
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Offline brewprint

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Re: Hops and pre boil volume
« Reply #2 on: February 27, 2017, 05:13:05 AM »
Beersmith does not factor in water absorption of the hops.  Typically, it would be reflected in the 'loss to trub and chiller' section, but I find that varies from recipe to recipe.

What I do for a 10 liter batch is plan on 10 liters into the fermenter and 1 liter loss to trub and hops.  This covers my loss for heavily hop loaded recipes easily enough and I can always overshoot the actual volume to the fermenter on those recipes which have minimal hop loading.

Then I must say that this is a serious flaw in the software. When I do 11 gallon batches of hoppy IPAs that take around 10-14 ounces per batch, that is going to have an impact. I also use hop bags when doing these.

I also account for 1 gallon loss due to trub. If I factor that in for hops that could potentially be another gallon.

The more that I use the software I see little things like this that could easily be changed. Hop absorption, pH calculations, acid malt additions, and kettle height in inches.

Offline Oginme

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Re: Hops and pre boil volume
« Reply #3 on: February 27, 2017, 05:37:26 AM »
As I stated in your other thread, the pH calculations is a new feature and I am sure it will be improved in new releases.  As far as hop/water absorption, if you have a study that shows the relationship, by all means, forward it to Brad.  I find that the difference between pellets and leaf, hard pressed pellets and soft pressed pellets, T-90s vs T-45s seems so variable in my meager studies and the ending water absorption is usually well within the error of my closest measurement that it may not be worth chasing so avidly, IMHO.  Even in one of my most heavily hopped recipes with a hop addition of 17 grams per liter of finished wort fits comfortably within my 1 liter of trub.

OTOH, I can see that if you are really stuffing a lot of low AA% hops into a recipe, that it would come into play eventually. 

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Offline brewprint

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Re: Hops and pre boil volume
« Reply #4 on: February 27, 2017, 05:03:09 PM »
Now you lost me.

When you use your example of 17 grams per liter, are you saying that you just throw them into the boil and that has no effect on your final volume in the trub? If that's the case, I'm sure that it would have a very significant effect on your final volume...as in a lot more trub.  Using hop bags not so much.

Either way, it should be accounted for. Why isn't it there? Check out the priceless calculator and just put in different hop amounts into your recipe. Watch the starting water volume change...fairly significantly.

We're not supposed to be just 'winging' it with this software. This is supposed to be 'the' brewing software. And it doesn't account for different amounts of hops!

Offline Oginme

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Re: Hops and pre boil volume
« Reply #5 on: February 27, 2017, 06:46:53 PM »
I don't use a bag for my hops and here goes the volume calculation (verified for my process):

OK, 17 grams per liter of hops for a 10 gal batch size is 170 grams of hops added.  Typical hop pellets have an apparent density of about 5 grams/ml, so this hop loading gives me a bump in volume of about 170/5 = 34 ml in a 11 liter finished volume.  This is about a .3% change in volume -- and that is on the highest end.  A typical recipe for me has about 29 grams of hops or about 6 ml of volume which is far less than my ability to accurately measure my volume using my dip stick.

This small amount can be easily buried in a small variation in boil off rate: 2.35 lph to 2.39 lph is 40 ml difference and is a very small change in the dial on my stove or affect of ambient temperature and well within a 2-sigma action limit for my process.

Likewise, it also falls within the variability for grain absorption.

I can appreciate that Priceless has added this variable, but in reality it would only be a major factor for whole leaf hops in a highly hopped recipe (where the volume would be somewhere in the range of 200 ml) and that would still end up buried in my extra liter of trub.  I've looked at his software, but I really like the single package of BeerSmith and find it much easier to track successive brews with BS2.

Honestly, there are a lot of other areas to improve the software and which would make a much greater impact to the average brewer.  There are a lot of places that *could* be modeled, but not all of them are enough of a difference to the majority of brewers who use the software or make enough of a difference to change their outcome.
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KellerBrauer

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Re: Hops and pre boil volume
« Reply #6 on: February 28, 2017, 05:35:53 AM »
Greetings All - I use a hop bag with my additions to help keep my plate cooler from clogging.  I have a 90 minute IPA recipe which includes 8 oz. of hops added over a 90 minute period.  I have had no noticeable or tangible difference in my final post-boil volume of 5.13 gallons.  So I agree with Oginme, any additional absorption is negligible - at least for my use of hop pellets.

Offline BOB357

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Re: Hops and pre boil volume
« Reply #7 on: February 28, 2017, 01:41:36 PM »
The only calculator I've seen that takes hops into consideration in volumes is BIAB Brewer's. They figure .04 gal./oz of hops and don't distinguish between leaf and pellets. While 5.12 oz. seems like a lot of liquid/oz. of hops, when you stop to consider that the hop debris/trub is suspended in a lot more liquid than it actually absorbs, I can believe it. 6.2 oz. of hop debris could very well cause a kettle loss of a quart of wort.
Bob

Offline brewprint

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Re: Hops and pre boil volume
« Reply #8 on: March 01, 2017, 05:32:16 PM »
The only calculator I've seen that takes hops into consideration in volumes is BIAB Brewer's. They figure .04 gal./oz of hops and don't distinguish between leaf and pellets. While 5.12 oz. seems like a lot of liquid/oz. of hops, when you stop to consider that the hop debris/trub is suspended in a lot more liquid than it actually absorbs, I can believe it. 6.2 oz. of hop debris could very well cause a kettle loss of a quart of wort.

Exactly. 1 quart per 5 gallon batch with 6 ounces is 1/2 gallon per 10 gallon batch. This is where the issue arises.

It surprises me that the posters above find this negligible. That along with the software not accounting for this blows my mind.

I also like using BS2 to keep everything in place. When I have to use other calculators to find correct numbers for pH and hop additions; I get annoyed.

Hopefully Brad is reading this. As I cannot believe that this issue has never come up before with the myriad of people using this software.

KellerBrauer

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Re: Hops and pre boil volume
« Reply #9 on: March 01, 2017, 05:57:14 PM »
Greetings All - I have not researched the calculators mentioned in this post.  As I stated, I use a hop bag holding a maximum of 1 oz. of hops per bag.  Therefore, there is no trub left in the kettle so it would be impossible to loose as much as you're suggesting. I'm guessing I would loose perhaps a 1/4 oz./oz. of hops.  But I'm not certain.  I'm brewing again in a week or so.  I'll check it to find out for sure and I'll post my findings.  In any case, whatever is lost is not enough for me to be concerned about.

Offline brewprint

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Re: Hops and pre boil volume
« Reply #10 on: March 01, 2017, 06:32:51 PM »
Greetings All - I have not researched the calculators mentioned in this post.  As I stated, I use a hop bag holding a maximum of 1 oz. of hops per bag.  Therefore, there is no trub left in the kettle so it would be impossible to loose as much as you're suggesting. I'm guessing I would loose perhaps a 1/4 oz./oz. of hops.  But I'm not certain.  I'm brewing again in a week or so.  I'll check it to find out for sure and I'll post my findings.  In any case, whatever is lost is not enough for me to be concerned about.

I'm referring to hoppy beers...not one ouncers. We've stated that 6oz of hops can absorb appoximately 1 quart of water.  Double the batch size and you're at 1/2 gallon. Add more hops...you are potentially losing a gallon in preboil.

I'm not referring to trub. I'm referring to absorption because if hop bags weren't used for that application you'd have to increase fermenter volume.

Offline Oginme

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Re: Hops and pre boil volume
« Reply #11 on: March 01, 2017, 07:07:06 PM »
IMHO, you are confusing water absorption with water displacement.  Hops may absorb a good amount of water, but that does not change the volume of the wort/hop mixture.  The only change in volume is the actual volume of the hops, since they do not dissolve in the wort.  Another thing people confuse is density versus bulk density.  Whole or leaf hops have a very low bulk density, taking up a lot of volume for a given weight of hops but when compressed, they don't take up much volume at all.

In my 37 years as a process engineer, process control engineer, and formulator of coatings, paints, inks and saturating solutions, I've seen people repeat this many times and end up scratching their heads trying to figure this out.  The volume increase in your kettle is only as much as the volume of the hops.  The difference comes out in the amount of trub created due to the absorption of the wort by the hops.  If you account for the trub volume ahead of time, there is no need to add additional water to the system to otherwise compensate for high hop loadings.  If you are adding additional water to account for the absorption of water by the hops, then what you are actually doing is accounting for additional trub volume that you will be leaving behind.  If you want to do this, change your loss to trub and chiller accordingly. 
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Offline brewprint

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Re: Hops and pre boil volume
« Reply #12 on: March 02, 2017, 04:59:26 AM »
What I'm referring to is exactly the same thing that happens while doing a full volume mash. If I would end up with 12 gallons for the pre boil based on grain absorption from  25 pounds of grain, I don't start my volume with 12 gallons! This is the argument that you're giving me here.

Hops absorb water just like the grain. The grain and hops are removed but still contain water from the original volume. I'm not confused here. I believe that you are actually going on about things that are meaningless.

If one does what you are saying, their final volume will be a significantly higher via volume, then you'd have to account for loss via trub and chiller like you stated.

Who does that? Seriously do you know anyone that wouldn't use some kind of a hop bag for 12 ounces plus on an 11 gallon batch of ipa?  Now you're just being difficult.

Offline jtoots

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Re: Hops and pre boil volume
« Reply #13 on: March 02, 2017, 05:48:12 AM »
I believe that you are actually going on about things that are meaningless....  Now you're just being difficult.

Woah, easy there bud.  Getting testy with someone that's trying to help you?  Not here, please.

KellerBrauer

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Re: Hops and pre boil volume
« Reply #14 on: March 02, 2017, 06:24:23 AM »
Greetings brewprint and I beg your pardon!  I happen to use hop bags for all my brews to help protect my plate cooler!  In fact, as I mentioned earlier, I brew a 90 minute IPA that includes 8 oz. of hops AND 8 hops bags which drained, as best as possible, and removed at the end of the boil.  So, yes, I do that and it works beautifully!

I also stated that I'll be brewing next weekend (I hope) and my brew will use 4 oz. of hops and 4 hop bags.  I will conduct an experiment on exactly how much liquid I loose from my batch.  I'll post my finsings at that time.  I'm guessing, however, my findings will be - as stated - insignificant.

Lastly, your original post asked a question and the answer has been posted in a variety of fashions and styles.  It's unfortunate it's not the answer your seeking.

 

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