Back to Shopping at NorthernBrewer.com

Taking Gravity Readings

I just recently started exclusively (cause i broke my second hydrometer) using my refractometer for taking gravity readings. I think I know the answer to my question but wanted some second opinions.

In the volumes used in home brewing, will there be various densities in a non mixed liquids? So for example, if you take a sample with a pipette from the top of the mash or pour some out of the valve from the cooler, they could be different right? The one from the valve is likely “heavier” than the top as the sugars settle to the bottom.

In a mixed or active biling where you have mixing, the density should be close to uniform, correct?

Thanks!

Yes and no, But I am going to skip past your question for a minute as there is no real reason to check the mash gravity. You can use a refractometer/hydrometer to check for complete conversion by taking sequential readings but unless you screw up real bad like mashing at 100f for example you are going to see complete conversion if mashing anywhere from 140-162f at 60 but for sure at 90 minutes if your leary. I find my mashes convert in under 30 minutes but I leave it for a full 60 as I have time and am in no rush.

I do however take a first wort running refractometer sample and a third wort sample to stop collecting wort before I go under 1.008. These samples are taken from the ballvalve where I do feel you will have more consistent sampling. Yes, I feel the fluid on the top of the mash may show a lower SG than you really have. So there you go.

Re: your comment about conversion time…there’s conversion and then there’s sugar profile. You can get pretty good conversion in half an hour or so, but the longer you mash, the more long chain dextrins are broken down and the more fermentable your wort will be. That’s one ason I always mash Belgian styles, for instance, for at least 90 min.

Is this true irrespective of mash temp?

Is this true irrespective of mash temp?[/quote]

Yep. In fact, lower temp mashes need more time just for conversion.

Per past experience and discussed before I have seen full attenuation with fast mashes at optima. The time thing starts to become semantics of a point or two at best. I will show my point and also concede to the fact that your point is valid although depending on actual need.
My intention is not to argue about the topic with you in any way, but to maybe further clarify my intended point regarding shorter mash times.

Typically where I am coming from is I have complete conversion and full attenuation that I require with a usual 60 minute simple infusion and this is what I practice and advocate for common ales, although I have seen a proper FG I require if mashing for 30 minutes at 145f and a PH of 5.2 at mash temp. (5.5 PH at room temp)in the past has shown me an OSG of 1.049 and it ferments right down to a FSG of 1.008 with US-o5. So temp and PH along with a mainly base 2 row grain bill became a factor over time in this case and over all my attenuation was 84% Why do I need to or want to go down to 1.006 if the discussion of over 30-60 minutes more is sustained? Then I am to understand this would/should boost fermentability to 86-88% and my FSG lands at 1.005-1.006?, but this was not true as shown by the below example as I hit the full attenuation expected for my grain bill and yeast type used as I expect an apparent attenuation of 81% with us-05.
Here is an example of two exact rye pale ales:
#1 OSG:1.049 FSG 1.008 1 sachet Us-05 84% attenuation, mashed for 30 mins@145f PH: 5.2
#2 OSG:1.049 FSG 1.008 1 sachet us-05 84% attenuation, mashed for 60 minutes@150f PH: 5.3
What exactly did the extra 30 minutes here add to increase the fermentibility or quality of my wort? Also the first running’s were exactly the same SG? Plus the lower temp was the one converted in 30 minutes. It shows that my statement holds water that SG, grain bill and actual need such as yeast type selected become the bigger factors to overall limit of fermentability and if needed then employ an ultra long mash to combat non-typical factors and stretch fementability out to the max if needed.

All of that being said you are still at the same rest temp but for longer to allow the further breakdown of dextrins but still not every chain even at 90+min and at some point you hit the plateau(30-60 minutes IMHO) and sure you boost your SG a few points and and/or ekk out 2-4% attenuation but at the expense of an extra 30 minutes to an hour and then again your yeast may not fully convert every sugar avalible as it hits its own limit of fermentability. What I am trying to convey is that far too many advocate a 90 minute mash and I have shown that I am receiving at/ above 100% conversion of the maltose needed in general uses. Do I need to hit 112-115% by mashing another hour is far over emphasized IMHO. So if you simply have 100+% conversion pull your wort at any time and go.

I feel 30 minutes or less mashing can create over 100% conversion and sugar profile needed as you have hit 100%+ does another hour of mashing create a few extra points sure. But you can make it happen if mash PH and temps are at optima. Again for 98% of the time I advocate a 60 minute mash where you hit 105-110% ----> this 30 minute thing is simply a 2% afterthought should be the main takeaway for newer brewers.

Here is a quote from Kai.
For a given rest time, there will be an optimum at which the most fermentable wort is produced. This optimal temperature depends, among other factors, on the length of the rest time. The shorter the rest, the higher the temperature optimum but also the less fermentable the wort will be

This agrees with my thought about plateau, temp and PH if in optima will need what I have shown is 30 minutes or less, true it also agrees with your statement regarding less ferment-able but it also disagrees with my actual findings of a fully ferment-able wort at anything over 100% conversion which I have found in 30 minutes or less per Kai’s spreadsheet. I think the missing defining factor here is grain bill and SG to be honest.

Now in come cases depending heavily on Grain bill you may need to goto 112-115% in order to chew down from high OSG’s true as you want all/most easily assimilable sugars. But in most common beers I think we can agree it can be done in 30 minutes and be fully converted and attenuation is full at 98% potential maybe. UNLESS you have a special circumstance mash then 90+ minutes may be required to hit 100% possible attenuation is what the difference starts to become.

Here is another quote from Kai that again asserts both points as it tells the viewer that a mash is fully converted at 15 min+. But then adds the fact to validate your point that there is a bit o conversion albeit small and he is stating this by saying conversion efficiency is increased after mash is starch negative. And per my own mashes to mirror 30/60/90 I have shown that your talking the ranges from usually around these numbers per Kai’s spreadsheet used.
a.30minutes = 100% conversion effic per SG readings and starch negative iodine test.
b.60 minutes = 105-110% " "
c.90+ minutes maybe = 112-115% " "
And depending on grain bill and yeast type you may or may not require 115% of sugar converted anyway. If a person is comfortable with 90 minute mash for all that is fine and gravy too, but it really comes down to your own brewday and the set of requirements that exact beer calls for.
"With today’s highly modified and thus enzymatic strong malts, the mash is generally converted after 15-30 min based on the rest temperature. Lower temperatures mashes convert slower than higher temp mashes of the same grist (see The Science of Mashing for further details). Most brewers do however mash 60-90 minutes since the fermentability still increases even after the wort itself is iodine negative. In addition to that longer mash times can also increase the conversion efficiency as they convert the harder to reach starch from the malt. It is always a good practice to check for conversion of the mash with a Starch Test. "

So I will wrap by saying a majority of beer styles can see 30-60 minute mashes and will produce what a brewer needs on an everyday basis with no degradation of quality or taste and very,very minimal degradation of conversion,attenuation if any depending on factors.

in addition to what Itspossible has stated, many craft breweries mash less than an hour, some as short as 15 minutes. Although i don’t practice this, i figure the extra time gives me time to prepare for the rest of my brew-day.

They stay at a rest temp for that amount, but they’re actually at mash temps for much longer due to lautering.

[quote=“Denny”]
They stay at a rest temp for that amount, but they’re actually at mash temps for much longer due to lautering.[/quote]

very true. didn’t think of that… :oops:

Denny,

That is not so. Commercial a mashout is conducted before lautering in most cases. This is so the brewer can stabilize the mash profile and it doesn’t continue to convert into perpetuity and cause a slide away from intended OG/FG until they can bring the temp up in the kettle.

[quote=“ITsPossible”]Denny,

That is not so. Commercial a mashout is conducted before lautering in most cases. This is so the brewer can stabilize the mash profile and it doesn’t continue to convert into perpetuity and cause a slide away from intended OG/FG until they can bring the temp up in the kettle.[/quote]

we start the sparge immediately after rest. we rest for an hour, but my boss said he’s used to resting for 15 minutes (at a different brewery), which made me assume the rest of our process was very similar (sparging immediately after rest).

Wow. This thread went crazy. I was just asking if the density of the top of a mash would be lighter when at the bottom of the mash was left undisturbed. My question wasn’t about conversion LOLOL.

[quote=“S.Scoggin”][quote=“ITsPossible”]Denny,

That is not so. Commercial a mashout is conducted before lautering in most cases. This is so the brewer can stabilize the mash profile and it doesn’t continue to convert into perpetuity and cause a slide away from intended OG/FG until they can bring the temp up in the kettle.[/quote]

we start the sparge immediately after rest. we rest for an hour, but my boss said he’s used to resting for 15 minutes (at a different brewery), which made me assume the rest of our process was very similar (sparging immediately after rest).[/quote]

If he is mashing for 60 then his profile is at plateau and will not change significantly from 60-90-120+ more minutes if conversion continues during sparge and I am just guessing here that the heat of the kettle is bringing the sparged wort to over 170F. If he truly mashed at a certain simple step mash for 15 minutes I am certain he would mash out to stop further conversion/attenuation away from his intended targets. Could you gather anymore anecdotal second hand information to add here? I’m sorry if you take that sentence as rude, but its true.
From your statements made your not at the control panel and therefore do not know exactly what the brewer is doing in regards to temp of the steps, a mashout/or not. Or other intimate details that only the commercial brewer himself could add to this discussion to give fact of real life examples of known conversion percentage, actual step temps sampled at what exact time period and PH of mash.Then a postboil SG and post ferment SG to give actual fact to the discussion.

Denny gave a statement above that I have refuted in regards to a commercial brewer mashing for 15-30 minutes and simply lautering without stabilizing the mash with no mashout.
The bottom line I have with Denny alone is give me proof that 90 minute mashes are an absolute necessity in real word brewing. Everything I read regarding this process, points to extremism and a rouge pattern that has never been followed in the commercial world, then why should a homebrewer. I say 90 minutes is a crutch advocated to newer homebrewer not willing to adhere to the simple things first like: a. PH b. temp Then c. time, not the other way around.

[quote=“ITsPossible”]
Could you gather anymore anecdotal second hand information to add here? I’m sorry if you take that sentence as rude, but its true.
From your statements made your not at the control panel and therefore do not know exactly what the brewer is doing in regards to temp of the steps, a mashout/or not. Or other intimate details that only the commercial brewer himself could add to this discussion to give fact of real life examples of known conversion percentage, actual step temps sampled at what exact time period and PH of mash.Then a postboil SG and post ferment SG to give actual fact to the discussion. [/quote]

I’m assistant brewer at the brewery I work for, it’s only me and the head brewer working. Like i mentioned - we mash for an hour and immediately sparge afterwards, our sparge water is 175 in the HLT and our kettle is turned on when we start running off, raising the wort in the kettle to near boiling. I know what we do in the brewery that I WORK FOR, but not the brewery my boss previously worked for (considering i’m one of 2 brewers on a 20bbl system, i’d say i’m familiar with our system). I can ask him more details of his previous employer and their steps, but no, I do not know the intimate details of someone else’s previous employer.

I did not mean to ruffle your feathers, and only wanted to add some info about commercial breweries because you were talking about them, and i happen to work for one. I’ll ask my boss weather or not he mashed out at the previous brewery, but i have a feeling you’d rather not hear it. I apologize for budding in on a public forum, and interrupting with info that i’ve gathered. Just like many, i’m only trying to learn here while offering what i’ve learned.

Dont, poke the sleeping giants!
No seriously, Myself and Denny have had this conversation in the past.
It seems its been a few years, so were going to hash it out again.
Sorry if I/we hijacked your thread man. Did you get your question answered?

Don’t get salty with me SS,
I appreciate any info if it is fact based and can contribute exactly to the thread.
Your clarity now, is factual. And it backs up my thought that your already plateaued wort profile is being in effect mashed out as soon as it hits the kettle. And if it had only been 15 minute mashed it is effectively brought to 170+ once it hits the kettle.

Don’t be an SOB SS. I cant post, poor me blah, blah. You know why I made the comment I did and it was because you were in fact throwing around anecdotal info. If you brought your last paragraph to the table initially, I would respect the fact that you are in a commercial setting and had positive info on either side of this discussion to add as you just did. Thank you for being a part of the community SS everyone brings beneficial experience to the table.

[quote=“ITsPossible”]
Do be an SOB SS. I cant post, poor me blah, blah. You know why I made the comment I did and it was because you were in fact throwing around anecdotal info. If you brought your last paragraph to the table initially, I would respect the fact that you are in a commercial setting and had positive info on either side of this discussion to add as you just did. Thank you for being a part of the community SS everyone brings beneficial experience to the table.[/quote]

I understand, and yes it was anecdotal. I hastily posted which happens from time-to-time. I just thought you responded in an unnecessarily rude way. So i responded ‘saltily’, I’ll be sure to be more thorough in the future…

hope there’s no hard feelings

cheers

Your gravy my man,

Usually homebrewing is anecdotal at best depending on your personal dedication level. So most posts on forums are a loose assortment of he said/ she said. But as I have stated, we have gone around the fence on this one before and as you can see on page one of this thread. I thought it time to lay out a book sized response to Denny. And hopefully bring clarity to my own thoughts on 30/60/90 minute mashing over on this side of the table.

Let me be super clear on this shorter than average post:
My advice to all is to mash for at least 60 minutes to attain the best of all paradigms present.
If you wish to mash for 30 or 90+ minutes, the choice is certainly there for you to individually make. This hobby is all about personal choice and exploration.

[quote=“ITsPossible”]
Sorry if I/we hijacked your thread man. Did you get your question answered?[/quote]

Oh, I don’t care it go hi jacked. Conversations are good people learn. But no I don’t think my question was answered lol :smiley:

Hey Ras,

I just checked out your blogsite. Looks pretty good.
I wanted to comment on your CDN/ thermapen deal.

I have used my CDN for over 5 years now and its still on the same batteries. The other day I ran my strike water to the tun and something was off with the temps as I usually have a loss of 8f and it was as though I had a loss of 3f which is impossible unless the ambient temp was 120f.
So I ran into the kitchen to quick check my Blichmann brewmometer that was on the kettle along with the CDN. Well sure enough my trusty Blichmann was off by 5f now and the CDN was right on still. I have dropped it many times and it once was dropped into the mash by a clumsy brew helper.
Still keeps ticking although it would be nice to have a thermapen at some point along with a NIST thermo and calibration cup just to be able to have confidence that I have accurate temps always as I am then calibrating at three points especially the 130f that comes closer to mash ranges.

Again may never need such a thing but check this out:

http://www.thermoworks.com/products/cal ... lbath.html
Back to Shopping at NorthernBrewer.com