[denny]

I guess I’ve found major influence from both the wort and the yeast. I feel that Lallemand knows their yeast, and I should be able to rely on their attenuation numbers. On the other hand, why would the LME manufacturers intentionally run their mash to create wheat extract with lower fermentability? I’m starting to think it is just variability of LME, and it’s coincidence that the Hefeweizen has had lower attenuation. Even though my attenuation is typically higher with other styles, I do get more variation when using LME than I did when I brewed all-grain. As dmtaylor pointed out, LME can be less fermentable than DME. I suspect that is what happens with age/staling. I haven’t used DME very much, but that might be worth a try. It should eliminate any staling issues.

They don't intentionally make it less fermentable. It's a byproduct of the process. FWIW, using the same yeast, i've gotten from 60-90% attenuation depending on the wort.

[neuse]

I just checked the dates on six Briess extract containers that I ordered on Nov 2. Date stamps: Two 2/23, one 1/23, two 7/23, and one 10/22. I’ll probably start using these in a week or two, and finish in a couple of months. I’m only guessing that age might lead to lower attenuation, but if it does, the dates on these could explain a lot.

[BrewBama]

I ck’ed the date on these: Oct ‘09

[BrewnWKopperKat]

I’m only guessing that age might lead to lower attenuation, but if it does, the dates on these could explain a lot.

Assuming they were stored all stored well, age is a consideration.  OTOH, if the 7/23 containers were stored poorly, the date won't matter.

With my limited experience (4 batches) with LME, I've found that Colby's idea of checking the color of an OG 50-ish sample to be effective in measuring freshness.  I can post the details if there's interest.

[denny]

I just checked the dates on six Briess extract containers that I ordered on Nov 2. Date stamps: Two 2/23, one 1/23, two 7/23, and one 10/22. I’ll probably start using these in a week or two, and finish in a couple of months. I’m only guessing that age might lead to lower attenuation, but if it does, the dates on these could explain a lot.

I'm hard pressed to be able to come up with a reason age would make a difference in attenuation.

[fredthecat]

i used to associate T58 as a pretty attenuative yeast, back before there were more clear average guidelines and people's reports on attenuation available. i just checked my really old batch notes on T58 and i got about 85% attenuation on a 1.065 beer that had 1lb of homemade candy (lol i know) sugar.

now fermentis lists it as "72-78%". i guess that sorta falls in line with it.

now im fully off topic but lol i used to enjoy T58 back in the day.

Anyone else? Remember the pepper flavour? I'm getting crazily tempted to bring back a blast from the past right now. some pale moderately strong t58 beer

[neuse]

I couldn't find any specific statement by experts on age affecting fermentability, so I did an AI chat. Here is the pertinent response:
While I don’t have a specific peer-reviewed reference for the exact statement you mentioned, I can provide some relevant information based on scientific knowledge and research.
1.   Aging of LME and Fermentability:
o   Liquid Malt Extract (LME), commonly used in brewing, undergoes chemical changes over time. As it ages, certain components within LME can break down or polymerize, affecting its fermentability.
o   The primary sugars in LME are maltose and maltotriose. These sugars are fermentable by yeast during the brewing process. However, as LME ages, some of these sugars may become less accessible to yeast due to chemical modifications.
o   Factors such as storage conditions (temperature, exposure to oxygen, etc.) play a role in how quickly LME ages and how its fermentability changes.
2.   Scientific Studies and Brewing Community Insights:
o   While there isn’t a specific peer-reviewed study solely focused on the aging of LME, brewing literature and experienced brewers provide insights.
o   Brewers’ Anecdotal Evidence: Many homebrewers and professional brewers report that older LME tends to yield beers with a sweeter finish. This suggests reduced fermentability.

So AI can't find specific references to confirm the change in fermentability, but it has inferred it from "Scientific Studies and Brewing Community Insights". I'm not sure what to do with that.

[BrewnWKopperKat]

Consider running the following experiment:

• Rapidly age a small amount of LME (see below for an idea on how to do this)
• create two OG 50-ish worts
• note the color of each (to compare to expected color for fresh LME
• ferment the worts (perhaps using a fast/forced fermentation test

This may help with rapidly aging the LME. 

A CBW® stored at 60° will experience minimal browning over a six month period, where as a CBW® stored at 90° on a hot summer day in a truck or warehouse will see exponential browning in just a few days.

https://www.brewingwithbriess.com/blog/secrets-to-keeping-your-liquid-extracts-fresh/