The Brew Matrix Experiment #2 - Mash Fines in the Boil x Kettle Trub in the Fermenter

[Bobby_M]

The conception of the system if interested; https://www.homebrewtalk.com/threads/multiple-concurrent-small-batch-brewing.729207/

This brew day is looking at what effects and/or differences there may be if you get a LOT of the fine mash particles into your boil (cloudy wort runoff from the mash) and also if you get a lot of the post boil kettle trub into the fermenter.

This Cream Ale, derived from the book "Brewing Classic Styles" was mashed in my 15 gallon eBIAB rig, relatively soft water profile acid adjusted to a 5.39 mash pH. The grain was milled as fine as a two roller mill can handle, approximately .012" gap. The kettles that would be filled with very clear, fines-free wort came from the mash recirculation hose directly before the mash was ever disturbed. The kettles with mash fines were filled AFTER the BIAB was pulled, squeezed and the wort stirred well. A point to note is that the wort you'd get in a typical BIAB batch would have an average amount of mash fines in the boil. These two example are the extremes that would never happen in a typical brew day but have the most likelihood of producing a detectable difference.

The other variable is the amount of kettle trub that makes it into the fermenter (minimal/none vs ALL). The two boilers below both received fines from the mash. The top one shows how much trub was left behind for the "clean ferment" as opposed to it all be stirred in well for the dirty ferment in the bottom kettle. The difference between them represents how much more trub the "dirty fermeter" got.

The "matrix" part of this project is that two different variable can be compared for four total output beers. The fermenters were filled with wort with the following characteristics. Note "dirty boil" has the mash fines in it. "dirty ferment" has the post boil kettle trub in the fermenter. The clean ferment beers were chilled in the kettle with immersion chilling and allowed to settle for about an hour before the clearest wort was siphoned into the fermenter. The "dirty ferment" worts were done the same way except the kettle was stirred while the transfer happened.

#1 DBCF (Dirty Boil, Clean Ferment)

#2 DBDF (Both Dirty)

#3 CBCF (Both Clean)

#4 CBDF (Clean Boil, Dirty Ferment)

Note that each boil did get an appropriate dose of whirlfloc at the end of the boil. The samples below represent what went into the fermenters. The picture was taken right after the fermenters got tucked away into the fridge to hold at 66F.

So far, the most interesting part is how much faster the two "dirty" fermenters started fermenting. The picture below is 20 hours after pitching 3 grams of US-05 into each fermenter. The two on the right, with visible krausen are the ones with all the kettle trub. The two on the left are the ones with no kettle trub.

 

[tdf]

How different was the original gravity of the clean vs dirty boil worts?

 

[Bobby_M]

How different was the original gravity of the clean vs dirty boil worts?

I measured a preboil of 1.039 on the wort coming out of the recirc (which is what was predicted) but I never remeasured the cloudy wort post bag squeeze to see if it picked up any more gravity. I suppose that came from the fact that I've tested this many times in the past and always saw the same gravity.

At the end of the boil, in fact the reason I had those small cups of wort to compare, I tested the OGs.. The two clean boil samples were 1.048 and the two dirty boil samples were 1.049 and 1.050. This either means squeezing the bag AND/OR the extra 5 minutes of mashout time raised the gravity or it was just a coincidental variation in boiloff rates.

 

[hotbeer]

Interesting. And just to be sure I'm understanding, those glasses are representative of what went into the FV's.

This next comment is just a jest. So please take it with a smile... For someone that says they are cutting back on the beer, that's still a lot of beer! I hope you still have a lot of friends that come to consume that for you!


Or do those boil kettles just look 5 gallon in the picture and are much smaller? I did see that you only used 3 grams of yeast and that seems more reasonable for a 1 to 1½ gallon ferment.

 

[balrog]

Really Really REALLY interesting about the fermentation starting with all the trub into the fermenter.

 

[hotbeer]

@balrog, it's really interesting to me that that seems to surprise you. I and I think others here have been saying we often do just put all the kettle including the hop matter into the FV.

The beers come out surprisingly clear and clean tasting. The differences between a batch that was done with minimal trub to the FV and everything to the FV are likely, IMO, to only be something one notes when doing side by side as this seems it will turn out. I've never had enough brewed close enough together to compare. But I was happy to drink all of them.

Judged on their own, I'd be confident they all will be good. Together though, one will probably have that little bit more to shine.

 

[balrog]

@balrog, it's really interesting to me that that seems to surprise you. I and I think others here have been saying we often do just put all the kettle including the hop matter into the FV.

The beers come out surprisingly clear and clean tasting. The differences between a batch that was done with minimal trub to the FV and everything to the FV are likely, IMO, to only be something one notes when doing side by side as this seems it will turn out. I've never had enough brewed close enough together to compare. But I was happy to drink all of them.

Judged on their own, I'd be confident they all will be good. Together though, one will probably have that little bit more to shine.

I've always dumped entire kettle to fermenter. Every time except once, and it was just too much time and effort without significantly noticeable reward to my plebeian uncultured untrained senses.

 

[corncob]

Very much looking forward to the results. Nice work.

 

[Bobby_M]

Interesting. And just to be sure I'm understanding, those glasses are representative of what went into the FV's.

Correct, those cups were filled from the siphon hoses going into the FVs.

This next comment is just a jest. So please take it with a smile... For someone that says they are cutting back on the beer, that's still a lot of beer! I hope you still have a lot of friends that come to consume that for you!

I'll probably end up drinking about 4 total pints out of this effort. All the matrix brews are destined for group tastings for the most part.

Or do those boil kettles just look 5 gallon in the picture and are much smaller? I did see that you only used 3 grams of yeast and that seems more reasonable for a 1 to 1½ gallon ferment.

The capacity of the boilers are 1.75 gallons.

Each of the FVs are 2 gallons with about 1.25 - 1.5 gallons of wort going in with the intention of packaging into 1 gallon Oxebar kegs filled to the brim.

 

[Bobby_M]

You can find people across this forum, on Reddit, and in general any space where brewers debate topics and here the extreme opinions.

1. Cloudy boils create off flavors.
2. Cloudy boils create cloudy beer.
3. Cloudy boils are no problem, my beer is clear.
4. Cloudy boils still create clear beer but the flavor may be degraded to some degree.
5. Trub in the fermenter creates off flavors.
6. Trub in the fermenter doesn't matter.
7. Trub in the fermenter creates cloudy beer.
8. Trub in the fermenter creates clearer beer.

These have all been stated. Everyone would be able to list the above statements in order of "probably true to probably not true" and we all know that list would be quite variable.

What I'm hoping to do is get sensory on this matrix of variables. Of course, it won't be conclusive but it will be slightly better than anecdotes from people who only brew one way. Reasons why it won't be conclusive:

It's only one beer style.
It's only one experiment.
People that read up on the experiment can't be sure I controlled any other variables adequately.
I may have an undisclosed motive to misinform.
A sensory panel may not have a significantly weighted preference for any one sample.

I haven't decided whether to reveal the variables to the panel first and then ask them to match the beers to which treatment they think derived them or if it should be completely blind and just ask to rate the beers in order with perhaps a one or two word descriptor next to each one.

 

[Deadalus]

You can find people across this forum, on Reddit, and in general any space where brewers debate topics and here the extreme opinions.

1. Cloudy boils create off flavors.
2. Cloudy boils create cloudy beer.
3. Cloudy boils are no problem, my beer is clear.
4. Cloudy boils still create clear beer but the flavor may be degraded to some degree.
5. Trub in the fermenter creates off flavors.
6. Trub in the fermenter doesn't matter.
7. Trub in the fermenter creates cloudy beer.
8. Trub in the fermenter creates clearer beer.

These have all been stated. Everyone would be able to list the above statements in order of "probably true to probably not true" and we all know that list would be quite variable.

What I'm hoping to do is get sensory on this matrix of variables. Of course, it won't be conclusive but it will be slightly better than anecdotes from people who only brew one way. Reasons why it won't be conclusive:

It's only one beer style.
It's only one experiment.
People that read up on the experiment can't be sure I controlled any other variables adequately.
I may have an undisclosed motive to misinform.
A sensory panel may not have a significantly weighted preference for any one sample.

I haven't decided whether to reveal the variables to the panel first and then ask them to match the beers to which treatment they think derived them or if it should be completely blind and just ask to rate the beers in order with perhaps a one or two word descriptor next to each one.

I am addressing your reasons why it won't be conclusive. The type of experiment that you are conducting is a randomized block design. The block is your batch and you have subdivided the block into four treatments (2 factors crossed). If you had created multiple batches (blocks) and applied the four treatments to each, the blocking controls for the other variables, the blocking accounts for them. The issue in formal analysis here is that you don't have multiple batches. I understand why that is prohibitive. Your results may still be informative but not rigorous in a statistical sense. Like a pilot study.

As far as what to measure, it is better to have that nailed down ahead of time to best test your hypothesis(es) and to avoid bias. Here you are testing cloudiness in the boil and trub in the fermenter as well as their interaction and their effects on what exactly? By stating the measure, for instance some measure of clarity at 30 days post-fermentation, you can avoid biasing later results. You don't want to measure something then decide to measure something else unplanned for based on the results of the first measure as that might be biased. You haven't started to measure much other than eyeballing the results so not a big deal really as the intent is to present it to raters but pointing all this out because having the experimental methods set helps to better design the experiment and it also provides strength to the results.

 

[DavidWood2115]

I haven't decided whether to reveal the variables to the panel first and then ask them to match the beers to which treatment they think derived them or if it should be completely blind and just ask to rate the beers in order with perhaps a one or two word descriptor next to each one.

Interesting experiment.

I would recommend giving each taster five (or six) pours: one of each with one (or two) randomly selected duplicate pour(s), all randomly labeled (i.e., so my "beer #1" has a <=20% random chance of being the same as your "beer #1").
Then conduct the trial in three steps:
1) Identify which two of one's pours are the same. If you give six pours, then it could be two pairs of duplicates or three of the same.
2) Rate the pours in overall quality, with notes on quality/defects.
3) Disclose the experiment and ask tasters to match the beers to the treatment.

The more pours you have the better you can identify randomness in the results.

 

[hotbeer]

I've always dumped entire kettle to fermenter. Every time except once, and it was just too much time and effort without significantly noticeable reward to my plebeian uncultured untrained senses.

I misread what you wrote originally. An all to frequent thing for me!

 

[CascadesBrewer]

Judged on their own, I'd be confident they all will be good. Together though, one will probably have that little bit more to shine.

The one time I did a split batch into the fermenter with lots of trub vs minimal trub, the batch with lots of trub fermented faster and cleared up much faster (this was an English Bitter). The batch with minimal trub fermented slower, stayed cloudy for a long time and had some off flavors.

It was not the best controlled experiment as it was a bit unplanned. I planned to split the batch with 2 yeasts, but after filling one 3 gal fermenter, I realized the pick up tube in my new-to-me 15 gallon kettle was too high to fill the second fermenter from the ball valve. The volumes were a little off and the second batch likely got more aeration when I dumped in the wort and trub.

On a note not related to the topic of this thread, the "True Weldless Bulkhead - With Edge Pickup Diptube" is an awesome product!
https://www.brewhardware.com/product_p/truebulkheadedge.htm

 

[Bobby_M]

I am addressing your reasons why it won't be conclusive. The type of experiment that you are conducting is a randomized block design. The block is your batch and you have subdivided the block into four treatments (2 factors crossed). If you had created multiple batches (blocks) and applied the four treatments to each, the blocking controls for the other variables, the blocking accounts for them. The issue in formal analysis here is that you don't have multiple batches. I understand why that is prohibitive. Your results may still be informative but not rigorous in a statistical sense. Like a pilot study.

As far as what to measure, it is better to have that nailed down ahead of time to best test your hypothesis(es) and to avoid bias. Here you are testing cloudiness in the boil and trub in the fermenter as well as their interaction and their effects on what exactly? By stating the measure, for instance some measure of clarity at 30 days post-fermentation, you can avoid biasing later results. You don't want to measure something then decide to measure something else unplanned for based on the results of the first measure as that might be biased. You haven't started to measure much other than eyeballing the results so not a big deal really as the intent is to present it to raters but pointing all this out because having the experimental methods set helps to better design the experiment and it also provides strength to the results.

This is all good stuff and I appreciate it. I have to consider the audience "fun factor" vs. having maximum experimental rigor as well. The original intent was to see if asking tasters to rate four different beers in order of preference would inherently yield some useful information, such as "60% of tasters preferred the beer that had kettle trub in the fermenter" or something like that. I would probably ask for some short feedback on why each sample was rated as such, or at least to say something about the favorite and least favorite. With a panel of both experienced high ranking BJCP judges and people that would describe beer as "smooth" or "good", it's hard to get data that parses perfectly.

I didn't plan to serve in clear cups because documenting the progress of these beers clearing over time and to what degree can be done without a panel. I can just pour them and take pictures. There's no question that there can be bias when you can see the beer. However, approaching it from a pragmatic perspective, the beer is the beer. People look at the beer they're drinking so it can look gorgeous and still taste bad and vice versa. I'm not sure I need to know which process produces a bad looking beer that tastes the best if you close your eyes.

 

[Bobby_M]

Interesting experiment.

I would recommend giving each taster five (or six) pours: one of each with one (or two) randomly selected duplicate pour(s), all randomly labeled (i.e., so my "beer #1" has a <=20% random chance of being the same as your "beer #1").
Then conduct the trial in three steps:
1) Identify which two of one's pours are the same. If you give six pours, then it could be two pairs of duplicates or three of the same.
2) Rate the pours in overall quality, with notes on quality/defects.
3) Disclose the experiment and ask tasters to match the beers to the treatment.

The more pours you have the better you can identify randomness in the results.

This is good, thanks. The wrinkle may be in the environment of the tasting. I was planning on having them all served via picnic taps at a meeting where people can serve themselves though I have a few other ideas based on the above.

Though there are four beers, I can set up a spreadsheet with all the members names already on it and have columns 1,2,3,4,5,6 (and have the same cup labels). I can label my taps A, B, C, D and just pour those four beers into any random four cup numbers being sure to write them down on the spreadsheet. Then randomly back fill the other two cup numbers with any of the four and just try to keep it random (or maybe just use a randomizer to pre fill in the spreadsheet).

It will make it challenging, in that I will need to manage the pours and hand out the beers, but it may be worth it. The only drag is that people won't be able to discuss the beers real time because they won't be talking about the same beers.

Thoughts?

 

[Bassman2003]

Thanks for doing this Bobby. I know the main reason the lodo crowd goes for clear wort is the staling risk of carrying the lipids from the brew process into the fermenter. I do not know how long you plan on judging these beers but I would guess that the "clean" beers might age better.

The fact that the "dirty" beers took off faster is kind of expected. I have learned that lodo worts often benefit from additional nutrient or do better with more healthy yeast cells. This makes sense as a lot of the "stuff" is stripped away and the yeast happen to like the "stuff". (sort of like Cheetos) But the "stuff" might end up being not positive for the end beer. Or not which is why we do these experiments!

 

[Bobby_M]

Thanks for doing this Bobby. I know the main reason the lodo crowd goes for clear wort is the staling risk of carrying the lipids from the brew process into the fermenter. I do not know how long you plan on judging these beers but I would guess that the "clean" beers might age better.

The fact that the "dirty" beers took off faster is kind of expected. I have learned that lodo worts often benefit from additional nutrient or do better with more healthy yeast cells. This makes sense as a lot of the "stuff" is stripped away and the yeast happen to like the "stuff". (sort of like Cheetos) But the "stuff" might end up being not positive for the end beer. Or not which is why we do these experiments!

I'll be sure to save it for long enough to taste over a longer storage period but the initial tasting is going to be in 5 weeks. I may put together a smaller panel of BJCP veterans to taste it one or two months later.

 

[tracer bullet]

Did you use a hop spider or let them roam free? Ultimately I'm asking what was the dirtiness going into the fermenter?

My brews tend to be in the AM, and so once I've immersion chilled I go grab lunch and let things settle. When I come back like an hour later and transfer to the fermenter I leave most of the trub behind. I don't freak out about it at all but leave most of it since it's pretty easy by then (a fairly clear delineation between liquid and solids).

I've read / seen that trub in general can indeed be beneficial or at least not worth worrying about. I've always been a little leery of adding a ton of hop material to the beginning of fermentation though.

And so back to the beginning haha wondering if you transferred a lot of hop material to the FV?

 

[CascadesBrewer]

just ask to rate the beers in order with perhaps a one or two word descriptor next to each one.

I say this is going to be the best strategy to get some useful data from the tastings. I suspect if you tried to do triangle testing with 4 different variables you would need to collect data from over a hundred tastings to get any meaningful statistics.

I've read / seen that trub in general can indeed be beneficial or at least not worth worrying about. I've always been a little leery of adding a ton of hop material to the beginning of fermentation though.

I feel the same. With my small batches, I usually often dump the entire contents of my kettle into the fermenter, but I pass it through a kitchen strainer that holds back most of the hop particles. Sometimes on my larger batches I will just leave behind whatever settles in the bottom of the kettle, or sometimes I will also pass the output of the ball valve through the strainer...and sometimes I use a hop spider to contain the hop pellets.

 

[doug293cz]

The only drag is that people won't be able to discuss the beers real time because they won't be talking about the same beers.

Not sure having people discuss the beers before turning in their evaluations is a good idea. Tasters may have their opinions swayed by others that they think have more refined palettes then their own.

Brew on

 

[Bobby_M]

Did you use a hop spider or let them roam free? Ultimately I'm asking what was the dirtiness going into the fermenter?

My brews tend to be in the AM, and so once I've immersion chilled I go grab lunch and let things settle. When I come back like an hour later and transfer to the fermenter I leave most of the trub behind. I don't freak out about it at all but leave most of it since it's pretty easy by then (a fairly clear delineation between liquid and solids).

I've read / seen that trub in general can indeed be beneficial or at least not worth worrying about. I've always been a little leery of adding a ton of hop material to the beginning of fermentation though.

And so back to the beginning haha wondering if you transferred a lot of hop material to the FV?

Since it is a very low IBU cream ale, I let them go free. Out of a 1.75 gallon PBV, it was 2.2 grams at 60 and 1 gram at flameout. The mixed up kettle trub that went into the FVs was hot/cold break and the small amount of hops. If it were a pale ale, I would have bagged the hops.

 

[Bobby_M]

Not sure having people discuss the beers before turning in their evaluations is a good idea. Tasters may have their opinions swayed by others that they think have more refined palettes then their own.

Brew on

Oh, I agree there. It's just that after everyone hands in their feedback cards, they'd want to discuss. I don't think I'm smart enough to compile the results in 10 minutes. Even so, if everyone has a different cup number per actual sample, I couldn't make an announcement of which was which. I suppose I could pull up the per person spreadsheet and let everyone see what they just tasted.

 

[mashdar]

Randomizing cups sounds good in theory, but in practice I suspect it'll be a huge PITA.

Just 0.02, feel free to ignore. You seem able to spin a lot more plates than I can.

 

[hotbeer]

I didn't plan to serve in clear cups because......

I think that's a good idea. Maybe even keep the ambient light low too.

I've got this thing about hazy beer. Though there are some I like, I do tend to have a built in dislike for haze in a beer. So those few that I actually like have to be way superior in some taste or something to get me to like them.

I'd think some others might also let haze sway their opinion in some way.

 

[Bobby_M]

I think that's a good idea. Maybe even keep the ambient light low too.

I've got this thing about hazy beer. Though there are some I like, I do tend to have a built in dislike for haze in a beer. So those few that I actually like have to be way superior in some taste or something to get me to like them.

I'd think some others might also let haze sway their opinion in some way.

What I was saying is that haze is a perfectly valid reason to have a more negative opinion about a beer that is known for clarity. Maybe two of the beers would taste almost identical and be rated equally but one is hazy and one is brilliant. I'd rather see the brilliant version of that similar beer score/rate higher because we're trying to determine brewing processes that produce the beers people want to drink.

edit: That's not to say that isolating the flavor impact isn't a reasonable academic exercise. This is perhaps what matters in the real world vs. what a scientist might find interesting. It reminds me a little of Brian Regan's bit about people saying "Don't go to the supermarket when you're hungry because you'll end up buying food that you like to eat when you're hungry".

 

[stamandster]

Thanks for doing this experiment!

 

[DavidWood2115]

Randomizing cups sounds good in theory, but in practice I suspect it'll be a huge PITA.

Just 0.02, feel free to ignore. You seem able to spin a lot more plates than I can.

OK, feel free to ignore this, but I spent a few minutes hacking together a way to make randomizing cups relatively painless for four unique beers and one duplicate pour. (OK, I actually spent much more than a few minutes, since my Python skills are not very good and my Latex skills have atrophied in retirement! But I (re-)learned a few things, so it's all good. Plus @Bobby_M has done so much for the community, I thought I would try to give back a little.)

Attached below is a PDF file that is formatted to print on Avery Presta 90505 round labels, which are easily ordered on-line. These can be peeled off and pasted on cups after they are poured.

Each row of labels is for one taster's group of beer cups. For example the labels in the first row are labeled "A#", where '#' is a randomly assigned number between 1 and 5. The second row is "B#", etc.

Here is the procedure I envision being used. If you end up trying these, I would love to hear your experience.

For four beers and N tasters:
1) Label the kegs/beers 1-4
2) Pour N + N/4 tastes of each beer. Keep each of the different beers together until they are labeled.
3) For each row of labels, peel off and paste the label on a cup corresponding to a cup of beer indicated ABOVE the label (Note: The first four labels are placed on beers 1-4, in order, so are redundant. The fifth label is the random duplicate, so that one needs to be placed on a cup with the correct beer.
3.5) (Optional) Re-map cups to make the test blind for the folks organizing the pours (see below).
4) Hand out each group of five cups to each taster.
5) Ask each taster to verify that the first letter on each cup's label is the same; if not, get them to swap as necessary. (**** happens!)
6) Ask them to identify the duplicate cups
7) Ask them to rate the pours in overall quality, with notes on quality/defects.
8) Disclose the experiment and ask them to match the beers to the treatment.
9) Pass out the key file so people can re-randomize.
10) Drink more beer!

Optional remapping step:
This step is to ensure that the organizers (i.e., those peeling and pasting the labels) get to participate in the experiment in a true blind fashion.
1) Select one or more auxiliary organizers to do the remapping.
2) For each cup in a group (e.g., all with the same first letter), peel and paste a label from a new row over the original label, taking care to first record the remapping. For example, if the original cups were labeled "A1, A4, A2,A3,A0) then paste over them with labels from another row, e.g., "W2, W0, W3, W1, W4", and write down the new mapping: A1->W2, A4->W0, A2->W3, A3->W1, and A0->W4. Note that it doesn't matter whether you keep the cups in order when you put the labels on; it just matters that you write down the remapping correctly (e.g., which W label covers up which A label, in this example).
Note: I haven't actually tried this to see if you can see the old label through the new. If so, a Sharpie should be able to put an end to that!


Note: the extra N/4 extra beers in step 2 is only exactly right if you use all 52 labels, otherwise you may need a few extra of one and a few less of another due to randomness.

If people are interested in this, I am happy to make the scripts, etc. available.

 

[corncob]

Whatever happened with this experiment?

 

[Bobby_M]

The beer wasn't quite ready for last month's meeting. It just needed a little more time to clear. I'll be serving it next Tuesday. I'm still making my final decision on how scientifically rigorous I am willing to get with this. I'm well intentioned while sitting at my computer, but when I put all the work into getting the kegs into a rolling cooler and get all the gas and picnic faucets set up, I'm going to be losing steam. I need this process to be relatively low stress and fun if I hope to continue brewing the 4-way splits. A good portion of the club is at the meeting for a social outlet as well and overdoing the technicality of the tasting may get me shunned.

 

[corncob]

The only real science being done today is called "engineering" anyway. Good enough is always good enough.

 

[corncob]

But speaking of clearing: did you notice any differences in how fast/how well they cleared?

 

[Bobby_M]

Two weeks into fermentation. Note that this picture was intentionally overexposed to see if differences could be better seen.

 

[Bassman2003]

Looking forward to the tasting notes!

 

[corncob]

So no major difference? Interesting.

 

[Bassman2003]

I do not think this experiment or trub in general is about beer clarity. It is more about staling over time and any flavor impacts. Most everything settles out over time to produce clear beer. Mashing and boiling are about extracting and leaving things behind you do not want. The boil has a lot of "stuff" that is drawn out of the wort. Logically one would want to leave the stuff in the BK which was kind of the point of the boil. But does it make a difference for the yeast and/or flavor if it makes it into the fermenter? The texts say to leave it behind but it is worth testing to see.

 

[Bobby_M]

Yeah, I think the point is that people design systems, and argue endlessly on forums regarding the same, to keep as much particulate matter out of the boil and/or fermenter. This one experiment is for me to see for myself, hopefully backed up by more tasters than just myself, whether more particulates in either of these places reduces the quality of the beer. While I'd like all the beers to taste exactly the same and continue down that same path as the beer ages for a couple months, I'm completely willing to modify my system to accommodate whatever makes better beer.

 

[hungupdown]

I measured a preboil of 1.039 on the wort coming out of the recirc (which is what was predicted) but I never remeasured the cloudy wort post bag squeeze to see if it picked up any more gravity. I suppose that came from the fact that I've tested this many times in the past and always saw the same gravity.

At the end of the boil, in fact the reason I had those small cups of wort to compare, I tested the OGs.. The two clean boil samples were 1.048 and the two dirty boil samples were 1.049 and 1.050. This either means squeezing the bag AND/OR the extra 5 minutes of mashout time raised the gravity or it was just a coincidental variation in boiloff rates.

We're gravity readings done by a hydrometer, or refractometer?
Having suspended solids, could increase actual density (as measured by hydrometer). While optical refractometer reading, which measures sugar from refraction angle, I guess wouldn't be affected by solids.

 

[tracer bullet]

While optical refractometer reading, which measures sugar from refraction angle, I guess wouldn't be affected by solids.

I'll choose my words carefully, but - I really think it does. My readings change, and the line is sharper, if I let my mash sample sit for a few minutes first. I'm not talking about it cooling, but I can see those particles settle out. The readings change and the line is sharper.

 

[Bobby_M]

We're gravity readings done by a hydrometer, or refractometer?
Having suspended solids, could increase actual density (as measured by hydrometer). While optical refractometer reading, which measures sugar from refraction angle, I guess wouldn't be affected by solids.

Easydens.