11

A non dissolvable solid like yeast in a liquid does not increase specific gravity. Its like dropping stones in to a water, the water still has the same density as it did before as the stones (and yeast in your example) are two separate phases. The solids simply displace the liquid but do not become a "part" of it, as in the example of salts or sugars or ...


10

Almost one third of your gravity is coming from maltodextrin powder. This stuff is non fermentable and should be used at a lower percentage. Also whatever yeast came with the kit is possibly old and unreliable. You probably won't get this batch to go any lower but you can make a couple changes and brew it again. Use only 5-10% of the total gravity points ...


8

You will need to add priming sugar if the beer has reached its terminal gravity with the yeast being used. In this example, despite the 80% attenuation the remaining 20% is not usually fermentable sugars. Its comprised of protein, dextrans and other molecules in solution that are largely ignored by your primary yeast strain. Lastly, reported attenuation ...


7

Wyeast 1968 is not a high attenuator to begin with - 67-71%, and has a temperature range of 64-72F (source). I think your temperature of 62F is the main culprit, especially if it's fluctuating, although there are other factors that contribute to the low attenuation. There are several changes you might consider next time: since you're using an English ...


7

Dissolved solids, such as sugars, increase the SG since they increase the mass of the solution without any significant volume increase. Suspended solids, like yeast, may increase or decrease the SG depending upon the relative density of the solids compared to the density of the liquid. In the case with the yeast, we know that yeast settles out eventually, ...


6

You may not be able to get it lower without using enzymes. Maltodextrin is non fermentable, and most dark malts have a large amount of non-fermentables from the kilning process. Adding some dry beer enzyme or beano will break down the complex sugars in the dark malt, and some of other nonfermentables, but you may end up with a thin beer afterwards. A more ...


4

Just because your thermometer is accurate at freezing temps doesn't mean it's accurate at mash temps. You need to get a certified calibration thermometer and check it at mash temps, about 150F. It might not be your thermometer at all, but until you verify it at mash temp you just don't know.


4

If you are truly being that diligent about your mash temps and hydrometers including knowing they are accurate, the ONLY thing left is a contaminating wild yeast/bacteria driving down the residual gravity. Take a bottle of beer and put it in a warm attic for a week. Chill it down overnight and open it up in the sink as a precaution. If the beer is super ...


4

In most cases dry hopping is or can be done after primary fermentation. So the beer is already fully attenuated prior to dry hops being added. That said I have added dry hops 3 days into an active ferment and still hit what I predicted to be my target FG. Furthermore, my calculated attenuation has always been as predicted when adding dry hops prior to the ...


4

Haven't seen any scientific stuidies on the topic, but I'd be very surprised if this was the case. For one thing, I don't know that hops affect yeast activity. Secondly, by the end of primary you've got a large, healthy colony of yeast. Adding an ounce or two of hops shouldn't make any difference. You might want to think about waiting until fermentation is ...


4

SG only measures the density of a solution relative to the density of pure water. It does not necessarily indicate dissolved sugars per se. So suspended particles as well as non-fermentable compounds (ie, maltodextrin, proteins, etc) contribute to SG without contributing to sweetness. This would include yeast, protein and anything else suspended within the ...


3

I'd suspect either a faulty thermometer that's reading deceptively low is to blame, or perhaps your mash water chemistry is really off and you aren't getting full conversion. For the former, check your thermometer in crushed ice-water to ensure that its reading 32F, and in boiling water to ensure its 212F. Don't be shocked if you can't get it to read 212F ...


3

Are you fermenting at high ambient temperatures? I've definitely noticed much more attenuation during summer months, when my basement is running at about 74F, compared to winter, when it's 68F. I've adjusted my recipes somewhat, but more my expectations and target styles. I now brew with Nottingham and saison yeasts in the summer, with an expectation of ...


3

No, the anti-microbial properties of hops do NOT affect yeast fermentation at all. Think of all the Double IPA's out there with IBU's in the 80's and higher. I knew a homebrew shop employee who made a double IPA that had 300 IBUs, including with a ton of late additions and dry hopping (it looked slightly green in the serving line) and it fermented out like ...


3

I think you are over thinking and and mis-interpreting the point of the "theory of mashing" article. That table regarding mash temp and attenuation is only specific to the wort tested. It's meant as a demonstration of how increasing temps may make a less fermentable wort. Fermentability of a wort is based on much more than temperature of the mash. The ...


3

There's many factors that effect attenuation. The %s are a ball park under normal conditions, factoring average unfermentables and ABVs. In theory all yeasts are capable of 100% attenuation of the fermentable sugars up to their ABV tolerance with a lot of nurturing. In your case 4 points off may not be that far out of scope. If the sweetness is balanced it ...


3

The Dupont strain is a kinda special beast. We found in an experiment on Experimental Brewing that you need to open ferment it to prevent the stall. Whether it's pressure or CO2 toxicity hasn't been determined. Assuming you're using an airlock, remove it and use a piece if foil loosely over your fermenter. That should fix it. https://www....


3

I have never found S-04 to be slow. Even on 500L batches, I've had beers with S-04 ferment dry in under 5 days. It also flocs out like a ton of bricks. Are you confident you don't have a contamination with another, more attenuative yeast? Are you also confident you got your OG and FG readings right, and calculated the AA right? As jsolarski says, without a ...


3

Yes it's totally possible. But I would expect a lower OG than you estimate. 1.071 is possible to drop out that quick but not very likely. Take a hydrometer AND refractometer reading on the finished beer and feedbthose values to the tool in BeerSmith under refractometer tools to get an actual OG estimate.


2

The analogy used with stones in water is a poor one, the reason being that stones are large and follow stokes law for particle size. They most certainly sink immediately, however, if you crushed up almost any rock or clay to the size of a yeast cell they would be suspended in the liquid and would contribute buoyancy to the hydrometer. The density change ...


2

If you have a pH meter, I suggest checking the pH. With a beer this small, it's very possible the grain wasn't sufficient to bring the pH down to levels the yeast agreed with. And seeing your target OG was low and 37% of your malt bill is grain that's already converted, it's possible that you wouldn't have noticed a big dip in efficiency. This would explain ...


2

That yeast needs a lot of O2 at pitching and rousing during fermentation. Add to that the fact that it's only been 5 days. Baby it along for another 2 weeks. It could also be dependent on your recipe.


2

I used to mash-in my berliner at 150 F, and then just let it cool down to 120 F or so. From there my souring process was pretty much identical to yours. But, I usually pitched straight L delbruckii, with a followup pitch of WLP630 or some other ale yeast(s). With multiple organisms at work, there's more potential for attenuation, and I would always see the ...


2

It all comes down to mash temp. Lower mash temps(145-148) will yield more fermentable sugars. Down side is you lower your mash efficiency and need to compensate with more grain or adjuncts. But you will have a substantially dry beer. Even with a iipa you should be able to hit 1.01.


2

Water may be the problem, but I'd focus on some easier solutions first. Confirming mash temp with a second thermometer. Mashing a little thinner (1.5-1.75qt/lb)and cooler (145-149F). And I would strongly recommend repeating one of the same beers you've already made so you can compare the end result with a prior result. THIS IS VITAL otherwise you really ...


2

I would focus on the yeast. How old were the yeast packs? Viability and cell count starts to drop off after just a few weeks. How big was the starter and what was the O.G.? Did you use a stir plate? There is a yeast calculator at Mr. Malty that I have found to be helpful. A stir plate helps quite a bit too. Make sure the temperature of your starter is near ...


2

To expand on my comment above: For most homebrewers, unless you're willing to drop some serious money on lab equipment, your measurements will be mostly limited to weights, volumes and specific gravity (and pressure, if kegging). Most of the numbers you'll be dealing with outside these things will involve calculations based on a best-fit equations for most ...


2

The attenuation rating of a yeast is meant for comparing one yeast to another and is not necessarily an indication of the attenuation you can expect That is far more dependent on the fermentability of the wort. Using the same yeast but changing the wort, I can easily get anywhere from 65-85% attenuation. Beersmith is doing nothing more than making a guess....


2

In my experience yeast gives up early when I see it drop out of high krausen / exponential growth / feeding phases in 1-2 days. It's the first sign for me to be diligent in taking readings and making adjustments to keep it going well. There's many reasons why this effects final gravity. Over all its speculated that when the yeast works too fast in growth ...


2

I have veiwed a few papers and this one contained similar proportions to other references but was the only one to contain a reference for the source of the proportions. Isolation and Characterization of Brewer's Yeast Variants with Improved Fermentation Performance under High-Gravity Conditions Which references: 8.6.1 Fermentability, Attenuation Limit of ...


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