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10

Factors Influencing Attentuation The apparent attenuation range published by yeast manufacturers shows how the yeast generally perform, under typical fermentation conditions. The following factors will affect the attenuation delivered by the yeast: Fermentability of the wort Maltotriose is only partially fermentable, and dextrins, caramelized sugars, and ...


9

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 ...


7

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 ...


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 ...


5

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 ...


5

The amount of yeast pitched and its viability has an impact on attenuation. Secondly, wort fermentability have an impact on attenuation. The extract you used this time could be more fermentable than what White Labs is basing their #s off of. These #s are also a guideline of what to expect not a hard fast rule of what you are supposed to do as a brewer. I ...


5

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 ...


4

Keep in mind that the attenuation rating listed for a yeast is more a way of comparing one yeast to another using a standardized wort than it a measure of what your attenuation will be. Wort fermentability is the key factor in attenuation, followed by yeast health, amount and type. Using anything other than the very lightest extracts can lead to reduced ...


4

Fermentability of the wort is probably the greatest factor in attenuation. With extract you should get pretty close to the mid-to-upper end of the attenuation range depending on specialty grain usage, but if you used any adjunct sugars that were highly fermentable you could exceed the listed attenuation. And yes, that is a typical range, not a set in stone ...


4

Glancing over the White Labs and WYeast charts, it seems that WLP410 Belgian Wit II and WYeast 3944 - Belgian Witbier have the lowest attenuation with the flavor profile that you're looking for. I've only used WLP410 Belgian Wit II though, so that would be my recommendation. It sounds like an interesting beer :) Good luck!


4

You can add more yeast anytime if you like, but 1.040 to 1.014 sounds like its done fermenting to me. The beer isn't going to get much more fermented than what it is now. The beer would have to be pretty hot for the yeast to get completely killed off. There should be plenty of yeast left to carbonate the beer. If you really feel that yeast is the reason ...


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

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, ...


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 ...


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

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

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

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 ...


3

Your final gravity will be influenced by a number of things. The typical attenuation range of the yeast is just one aspect. How thick/thin and warm your mash is (or the overall fermentability of your LME or DME) will play a significant roll. Fermentation temperature and aeration of the wort before pitching will also be significant. As JackSmith stated, the ...


3

The yeast strains usually come with an apparent attenuation range, not an exact value. For instance, something like 70-75%, 67-70%, etc. I always hope to hit the lower end of that range. For example, if I start at 1.050 and use a yeast with 73-80% apparent attenuation, I expect to end up in the range of 1.010 - 1.014. Sometimes I go a point or two lower ...


3

Attenuation is far more dependent on the fermentability of the wort than the rating of the yeast. Those yeast ratings are merely a way of comparing one yeast to another using a standardized wort, and don't really reflect the actual attenuation. If you want low attenuation, mash at a high temp or use grains that have a high degree of unfermentability.


3

You know that your mean potential FG is 1.012 (this is an example, when designing your batch you can predict your FG more or less). You can find the amount of priming sugar needed according to style and temperature from here: http://kotmf.com/tools/prime.php Now that you know the amount of priming sugar needed, all you have to do is the following: OG ...


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 ...


2

According to Shea Comfort, no, it doesn't. At least not by itself. It will eat leftover simple sugars that the beer yeast couldn't get to due to a harsh environment, but it will definitely not ferment maltotriose. There are enzymes that you can add that will break the maltotriose down into something that it will consume, but you need to be particularly ...


2

Unfortunately, not all extracts are created the same. I think what you are seeing is that your extract is not as fermentable as the extract created by say Wyeast to give you their range of attenuation. You can easily email Wyeast or WhiteLabs to ask them about the conditions used to get the attentuation ranges. The are generally very helpful with that sort ...


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

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

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 ...


1

"what is the importance of understanding yeast attenuation?"....Yeast attenuation is determined by the yeast lab under laboratory conditions, and it is only a way of comparing one yeast relative to another using the same wort. You may or may not achieve the attenuation that is listed for the yeast. It may be less, it may be greater than listed. That ...



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