Rehydrating us-05 - temperature and time

[OrdinaryAvgGuy]

I've been using liquid yeast since I started brewing and have finally decided to give US-05 a try.

I'm reading conflicting information on the hydration process.

First, some suggest rehydrating with boiled sterilized water cooled to 105°F while others suggest a lower temperature such as 95°F or less. The manufacturers instructions suggest 74°F - 86°F. Are those who are suggesting a higher temperature simply accounting for temperature drop when adding the yeast? I'm not sure where they are coming up with these numbers when the instructions state 80°F ± 6°F.

Also, the instructions state that the rehydration process should take between 45 mins to 1 hour. Others online say only hydrate for 15 mins.

 

[stpug]

Check out this post and decide for yourself what temperature to use:
https://www.homebrewtalk.com/f39/fermentis-dry-yeast-users-433698/index6.html#post5550723

I have personally had better experience with the higher temps (105) mentioned in the linked post than the cooler (~80) temps suggested by manufacturers. Hope this helps.

 

[BrewerE]

1 cup of 80-85* boiled water
Dump in, stir after 15 min
Stir and pitch at around 30 min

I do it for s-04 and s-05, have always had good, fairly quick starting fermentation

 

[OrdinaryAvgGuy]

Check out this post and decide for yourself what temperature to use:
https://www.homebrewtalk.com/f39/fermentis-dry-yeast-users-433698/index6.html#post5550723

I have personally had better experience with the higher temps (105) mentioned in the linked post than the cooler (~80) temps suggested by manufacturers. Hope this helps.

It just seems odd that some Jamil and Chris suggest 105° when the manufacturer suggests a much lower temperature. One would think that the manufacturer would know what is optimal for their product.

 

[stpug]

It just seems odd that some Jamil and Chris suggest 105° when the manufacturer suggests a much lower temperature. One would think that the manufacturer would know what is optimal for their product.

You are right, and the quoted section from the book agrees with you.

Rehydration generally ranges from 95 to 105* F (35 to 41* C) although some manufacturers suggest a lower temperature range. The ideal temperature for each dry yeast product can vary, and you should strive to find out from the manufacturer what temperature is optimal for their product.

That's why I suggested that once you are armed with the information, you decide how to proceed yourself. I've had visually better success with rehydrating at warmer temperatures (~105) with Mangrove Jack yeasts than their suggested lower temp (~85). The frothy, bubbly, creamy consistency was never attained with the manufacturers temps. Additionally, I've seen a slightly smaller lag time with the warmed rehydration temps but we're talking a difference of about 15 hours versus 18+ hours (still longer than I'd hoped for).

In the end, I think you could pick a safe temperature between 80-105 and rehydrate and pitch. Maybe try lower this time to be closer to manufacturers. Next time, you could try a higher temp just to see the difference it makes - if any.

 

[OrdinaryAvgGuy]

You are right, and the quoted section from the book agrees with you.


That's why I suggested that once you are armed with the information, you decide how to proceed yourself. I've had visually better success with rehydrating at warmer temperatures (~105) with Mangrove Jack yeasts than their suggested lower temp (~85). The frothy, bubbly, creamy consistency was never attained with the manufacturers temps. Additionally, I've seen a slightly smaller lag time with the warmed rehydration temps but we're talking a difference of about 15 hours versus 18+ hours (still longer than I'd hoped for).

In the end, I think you could pick a safe temperature between 80-105 and rehydrate and pitch. Maybe try lower this time to be closer to manufacturers. Next time, you could try a higher temp just to see the difference it makes - if any.

I see what you are saying. I'm however seeing several home brewers suggest 105°F for the US-05. Perhaps they are using what is being said in the Yeast book without taking into consideration the manufacturers instructions?

 

[stpug]

I see what you are saying. I'm however seeing several home brewers suggest 105°F for the US-05. Perhaps they are using what is being said in the Yeast book without taking into consideration the manufacturers instructions?

That very well could be. To me, it seems the moral is that as long as you're within a "safe" rehydration temperature range then your results will be successful. I suspect there WILL be some difference in yeast health, viability, vitality, and/or surviving cell count depending on rehydration temperature but how this can be assessed scientifically would require a small investment and study time. For the "lay person" (like myself), I'm left to assessing my results based on visual and sensory "inspection"; i.e. how the yeast cream looks after rehydration, how the lag time proceeds, how the fermentation proceeds, how the attenuation completes, and how the resulting beer tastes. It's not really scientific, but then again the science is much less important than making a good beer . Afterall, some folks pitch it dry directly into the wort and make beer. According to the experts and scientifically-minded, you will lose anywhere from 35-50% of the cell count by doing this but obviously folks are still making beer this way.

Again, I would simply recommend following the Yeast procedure but use the manufacturers recommended temp range this first time. Next time you use US05 from dry form, try the higher rehydration temperature and, using visual and sensory factors, compare your results this time with next time to determine which YOU prefer.

HTH!

 

[OrdinaryAvgGuy]

That very well could be. To me, it seems the moral is that as long as you're within a "safe" rehydration temperature range then your results will be successful. I suspect there WILL be some difference in yeast health, viability, vitality, and/or surviving cell count depending on rehydration temperature but how this can be assessed scientifically would require a small investment and study time. For the "lay person" (like myself), I'm left to assessing my results based on visual and sensory "inspection"; i.e. how the yeast cream looks after rehydration, how the lag time proceeds, how the fermentation proceeds, how the attenuation completes, and how the resulting beer tastes. It's not really scientific, but then again the science is much less important than making a good beer . Afterall, some folks pitch it dry directly into the wort and make beer. According to the experts and scientifically-minded, you will lose anywhere from 35-50% of the cell count by doing this but obviously folks are still making beer this way.

Again, I would simply recommend following the Yeast procedure but use the manufacturers recommended temp range this first time. Next time you use US05 from dry form, try the higher rehydration temperature and, using visual and sensory factors, compare your results this time with next time to determine which YOU prefer.

HTH!

Thanks for weighing in on this.

I'm going to first try rehydrating on the higher end of the manufactures suggested instructions @ 86°.

What about the length of time? The Yeast book suggest a total time of 20 mins while the US-05 instructions state a total time between 45 and 60 mins.

 

[stpug]

Thanks for weighing in on this.

I'm going to first try rehydrating on the higher end of the manufactures suggested instructions @ 86°.

What about the length of time? The Yeast book suggest a total time of 20 mins while the US-05 instructions state a total time between 45 and 60 mins.

According to the book, yeast will start using their sterol reserves immediately upon rehydrating, and because of this, I would aim for the shorter time of ~20 minutes. By that time, the cells should be able to regulate what passes their cell membrane which is the single-most important reason for rehydrating. The quicker they are put into the wort with the ability to regulate what passes their membrane the more sterols they are able to reserve for the stressful environment down the road.

 

[sablesurfer]

Why are you rehydrating at all?? (Yes, I am going there.) -05 can be, and is made to be, pitched dry right into your aerated wort. Says so right on the package....

Second bit of instructions from site
"Alternatively, pitch the yeast directly in the fermentation vessel providing the temperature of the wort is above 20°C (68°F). Progressively sprinkle
the dry yeast into the wort ensuring the yeast covers all the surface of wort available in order to avoid clumps. Leave for 30 minutes, then mix the
wort using aeration or by wort addition."

Instructions on packet
"Pitching: Sprinkle into wort."

Now, I have recently come to be educated on the amount of 05 to pitch. The debate about a second packet starts right around 1.060 from what I can tell.

 

[stpug]

Why are you rehydrating at all?? (Yes, I am going there.) -05 can be, and is made to be, pitched dry right into your aerated wort. Says so right on the package....

Second bit of instructions from site
"Alternatively, pitch the yeast directly in the fermentation vessel providing the temperature of the wort is above 20°C (68°F). Progressively sprinkle
the dry yeast into the wort ensuring the yeast covers all the surface of wort available in order to avoid clumps. Leave for 30 minutes, then mix the
wort using aeration or by wort addition."

Instructions on packet
"Pitching: Sprinkle into wort."

Now, I have recently come to be educated on the amount of 05 to pitch. The debate about a second packet starts right around 1.060 from what I can tell.

I suspect that the package instructions on most dry yeast packets fall into the same category as the instructions on the vials and smack packs of liquid yeast. Vials and smack packs say that it's good enough for 5 gallons of beer, but we have seen sufficient evidence that this is not the whole truth. I think the same can be said of dry packet instructions - the packet instructions don't give the whole truth.

 

[OrdinaryAvgGuy]

Why are you rehydrating at all?? (Yes, I am going there.) -05 can be, and is made to be, pitched dry right into your aerated wort. Says so right on the package....

Second bit of instructions from site
"Alternatively, pitch the yeast directly in the fermentation vessel providing the temperature of the wort is above 20°C (68°F). Progressively sprinkle
the dry yeast into the wort ensuring the yeast covers all the surface of wort available in order to avoid clumps. Leave for 30 minutes, then mix the
wort using aeration or by wort addition."

Instructions on packet
"Pitching: Sprinkle into wort."

Now, I have recently come to be educated on the amount of 05 to pitch. The debate about a second packet starts right around 1.060 from what I can tell.

I've been using the Wyeast smack packs which contain 100 billions cells (assuming its relatively fresh and not mishandled). The directions on the package says that you can directly pitch into up to 5 gallons of 1.060 wort. However, many, including myself, make a starter to increase the cell count to around 200 billion which is what many people use for a 5-6 gallon batch.

In the past I have directly pitched Wyeast smack packs directly into the wort and it made beer. So yes, what is said on the instructions does work. However, you are likely under pitching using this method.

The same could be said with US-05. A packet of US-05 contains +-200 billion cells. One experiment (by Jamil I believe) suggest a 50% kill off rate when the yeast are not rehydrated. You can follow the easy instructions by sprinkling directly onto the wort which leaves you with 100 billion, or the same count as a direct pitch Wyeast. This once again means you have under-pitched.

I'm sure either way works but I'm going with the rehydration method because for a couple ounces of water and a few minutes it's a cheap insurance policy to ensure that you are not under-pitching.

Then again, as you can tell by the question that I am asking, this will be my first attempt at using US-05 so what do I know besides what I have read?

 

[boydster]

I actually emailed the temperature question to Fermentis a while ago and they never responded. Maybe I will try again.

 

[Hopper5000]

Something that I was wondering about myself is thermal shock when rehydrating the yeast. I recently rehydrated a couple of packets of 05 at about 85F which sat for approximately 30min before pitching (I usually use liquid yeast I should mention). As I was dumping this into my 68F wort I was wondering if this would cause thermal shock and the yeast to have some issues because of that. This was a 1.060 beer. Anyone have thoughts on this?

 

[boydster]

You can add wort to the yeast in small increments to bring the temp down.

 

[Puddlethumper]

Something that I was wondering about myself is thermal shock when rehydrating the yeast. I recently rehydrated a couple of packets of 05 at about 85F which sat for approximately 30min before pitching (I usually use liquid yeast I should mention). As I was dumping this into my 68F wort I was wondering if this would cause thermal shock and the yeast to have some issues because of that. This was a 1.060 beer. Anyone have thoughts on this?

+1 to Boydster's advice. Get your yeast within 15F of the wort temperature before pitching. The closer they are to the same temperature the better.

 

[boydster]

So I just sent another message to Fermentis asking why their yeast says to rehydrate at a temperature that is so much lower than what would be considered "optimal" for other dry yeasts. I suspect they suggest 80F on the package because by the time the hydration process is complete, the small amount of water you use will have a chance to naturally lower down to an adequate pitching temperature. It's only 115 ml of water (10 x the weight of the yeast, or 10 x 11.5) and it's being left out for 30 minutes at room temp. The "Sprinkle into wort" instructions on the package are what lead me to believe they are taking an "ease of use" approach with their instructions. It's easy to just sprinkle, and it'll work. It's easy to add the yeast to 80F water for 30 minutes and then dump it into the wort, and it'll work. That's just my theory though, so I really hope they actually answer me this time.

 

[OrdinaryAvgGuy]

So I just sent another message to Fermentis asking why their yeast says to rehydrate at a temperature that is so much lower than what would be considered "optimal" for other dry yeasts. I suspect they suggest 80F on the package because by the time the hydration process is complete, the small amount of water you use will have a chance to naturally lower down to an adequate pitching temperature. It's only 115 ml of water (10 x the weight of the yeast, or 10 x 11.5) and it's being left out for 30 minutes at room temp. The "Sprinkle into wort" instructions on the package are what lead me to believe they are taking an "ease of use" approach with their instructions. It's easy to just sprinkle, and it'll work. It's easy to add the yeast to 80F water for 30 minutes and then dump it into the wort, and it'll work. That's just my theory though, so I really hope they actually answer me this time.

Your theory makes a lot of sense to me. In order to avoid making the hydration process sound complicated they lowered the recommended temperature and left out the "cool to room temperature" step.

Also, allowing to cool naturally (without ice bath) takes even longer with the additional 20° - increasing the chances of something airborne taking over or yeast cells dying off.. Just a wild guess.

Keep us posted and let us know if you receive a response.

 

[OrdinaryAvgGuy]

Something that I was wondering about myself is thermal shock when rehydrating the yeast. I recently rehydrated a couple of packets of 05 at about 85F which sat for approximately 30min before pitching (I usually use liquid yeast I should mention). As I was dumping this into my 68F wort I was wondering if this would cause thermal shock and the yeast to have some issues because of that. This was a 1.060 beer. Anyone have thoughts on this?

If they were rehydrated at 85 degrees in 115 ml of water (I'm assuming) my guess is that it should have cooled down to room temperature within the 30 mins?

Did you check the temp before pitching?

 

[BrewerE]

I would also wonder about thermal shock if starting so high.

I don't know where you guys are getting that Fermentis says 105* and 45-60 min...

http://www.fermentis.com/wp-content/uploads/2012/02/SFA_US05.pdf

Right there, 80* +/- 6, pitch at 30min

Like I said earlier, I've followed these instructions every time and have never had problems with 05 or 04.

 

[boydster]

I asked Fermentis why they DON'T indicate that high of a temp, given that many other authority figures do. I have also never seen a credible source recommend 45-60 minutes - I have seen recommendations to pitch as close to 30 minutes as possible to get the most from the nutrient reserves in the packet.

 

[cheddarhed3]

This thread is awesome. You guys are giving this newbie confidence to rehydrate my US-05 and just go for it. I appreciate reading all the great input. Cheers.


Sent from my iPhone using Magic and deception.

 

[OrdinaryAvgGuy]

I would also wonder about thermal shock if starting so high.

I don't know where you guys are getting that Fermentis says 105* and 45-60 min...

http://www.fermentis.com/wp-content/uploads/2012/02/SFA_US05.pdf

Right there, 80* +/- 6, pitch at 30min

Like I said earlier, I've followed these instructions every time and have never had problems with 05 or 04.

Sprinkle the yeast in minimum 10 times its weight of sterile water or wort at 27°c ± 3°C (80°F ± 6°F). Leave to rest 15 to 30 minutes.
Gently stir for 30 minutes, and pitch the resultant cream into the fermentation vessel.

I read this as let it rest for 15-30 mins and then stir for an additional 30 mins. No? Maybe I'm interpreting it wrong.

 

[BrewerE]

I see it now. My brain read this 'for' as an after "Gently stir for 30 minutes".

That being said, I've never had an issue and it is usually going strong by 12hrs.

 

[boydster]

I let it sit for 15 minutes, then stir, let it sit for another 5-10 minutes, stir again then pitch.

 

[stpug]

I let it sit for 15 minutes, then stir, let it sit for another 5-10 minutes, stir again then pitch.

Same process here with the added step of acclimatizing the yeast to within about 12°F of the wort temp prior to pitching.

 

[wildactbrewer]

I've only used dry yeast once and it was Nottingham. I too was a little confused on the re-hydrating so I just treated it like i would have a starter...sort of.

When I started my boil I added 1 cup of 100F boiled water to 1 packet of Notty. I then gave it a little stir after 30 mins and again at 15. I checked the temp again before I added to my chilled wort(70F) and it was 85 degrees. It took off within 8 hours(could be due to the nature of the strain). But either way the beer is still looking good after one week!

P.S. I stirred every time I had a hop addition. Additions change based on the style of beer but in this instance the 60-30-15-flameout schedule worked.

 

[boydster]

Same process here with the added step of acclimatizing the yeast to within about 12°F of the wort temp prior to pitching.

Good call

 

[OrdinaryAvgGuy]

I see it now. My brain read this 'for' as an after "Gently stir for 30 minutes".

That being said, I've never had an issue and it is usually going strong by 12hrs.

The directions could have been better written. Perhaps "Leave to rest 15 to 30 minutes and then gently stir for 30 minutes".

I'm sure there are 100's of different temperature and time variables that will successfully create beer. Heck, you can apparently just throw it on the wort dry, kill half the yeast and still make beer!

I'm going with the advice from the book Yeast combine with my newfound knowledge thanks to you guys!

It's going to go something like this:

1. Boil & cool 115 ml of tap water to 86°.
2. Sprinkle room temperature yeast packet evenly across surface and allow to rehydrate for 15 mins
3. Stir around for 5 mins
4. Check temp and lower if necessary by adding small amounts of cooled wort
5. Pitch into wort once cooled down to similar temperature

As Stpug suggested, I'll try a slightly higher temp next time just to see how it differs.

 

[RmikeVT]

You are right, and the quoted section from the book agrees with you.


That's why I suggested that once you are armed with the information, you decide how to proceed yourself. I've had visually better success with rehydrating at warmer temperatures (~105) with Mangrove Jack yeasts than their suggested lower temp (~85). The frothy, bubbly, creamy consistency was never attained with the manufacturers temps. Additionally, I've seen a slightly smaller lag time with the warmed rehydration temps but we're talking a difference of about 15 hours versus 18+ hours (still longer than I'd hoped for).

In the end, I think you could pick a safe temperature between 80-105 and rehydrate and pitch. Maybe try lower this time to be closer to manufacturers. Next time, you could try a higher temp just to see the difference it makes - if any.

I agree with the above. I like the higher temp because I find the yeast make a much nicer slurry and re-hydrate more favorably. I then put the cup in a small ice bath until the temp gets close to my wort temp (65-70 F) and pitch. I've always had much better results with re-hydrated yeast over pitching dry. Better tasting beer and shortened lag time.

 

[Hopper5000]

If they were rehydrated at 85 degrees in 115 ml of water (I'm assuming) my guess is that it should have cooled down to room temperature within the 30 mins?

Did you check the temp before pitching?

No I didn't check the temp, just assumed. There was a bit longer of a lag phase than usual but it's going strong now.

 

[OrdinaryAvgGuy]

No I didn't check the temp, just assumed. There was a bit longer of a lag phase than usual but it's going strong now.

Yeah, if you rehydrated your yeast at 85 degrees then let it sit at room temp for 30 mins then you were likely in the low 70's by the time you pitched it.

 

[Hopper5000]

ya i wasn't really that worried, it was just a thought... i was more thinking about it being a factor when hydrating at 100F or so

 

[boydster]

So I figured I should follow up on this thread. I just got an email back from Fermentis. Below is what I sent them, and the response I received.

Me:

Hello, I asked this question several weeks ago and have not heard back. I have seen multiple sources that say dry yeast should be hydrated at temperatures that are warmer than Fermentis suggests for US-05 and S-04 (sources say all dry yeast have an optimal temp range of 95-105F for hydration, while Fermentis recommends temps closer to 80F). I am trying to understand why the discrepancy. Is there something different about Fermentis yeasts? Or is the recommendation based on ease of use? Would I do any harm, or would I potentially do my yeast a favor, if I were to rehydrate it at 100F?

Please let me know. If it really is the case that Fermentis yeast is different, I think that is really neat and I would love to know what exactly it is that differentiates your yeast from others with respect to optimum hydration temperature.

Regards,

Fermentis:

I am sorry to come back late with the answer.

First of all, we would never recommend any procedure that could potentially harm the yeast and alter your beers. Second, I don’t know what the competitors are doing, but I can confirm that our hydration instructions are validated by our R+D Center, located in Lille, North or France and several Institutes and Universities that have been collaborating with us during the last 15 years. Our yeasts and use recommendations protocols were also validated by the market for 15 years; prove of that are the thousands of homebrewers, microbreweries, regional and industrial breweries that currently chose our yeasts, making Fermentis the leader in this segment all around the world. In addition, we belong to the Lesaffre Group, which is world largest active dry yeast manufacturer. In fact, the group is producing active dry yeast for other industries since the beginning of the 70’. We are pioneers in this field in terms of quality and innovation.

Despite my words above, it is not my intention to answer your question, just trying to impress you. The explanation is that we recommend this hydration temperature based on exhaustive tests at temperatures more comfortable with the brewing process. It is safe, secure and do not harm your yeast. The reason why we can do it and not our competitors is not completely clear for me, but it is for sure related to the production process (mainly the drying of the yeast) and not to the strains themselves. Our yeasts can tolerate lower hydration temperatures due the Lesaffre technology.

Hope my words can answer your questions.

I wish very nice brews.

Best wishes,

 

[stpug]

So I figured I should follow up on this thread. I just got an email back from Fermentis. Below is what I sent them, and the response I received.

Me:


Fermentis:

Clear as mud

 

[OrdinaryAvgGuy]

So I figured I should follow up on this thread. I just got an email back from Fermentis. Below is what I sent them, and the response I received.

Me:


Fermentis:

Sounds like a whole lot of fluff. So their dehydration process enables them to offer a product that hydrates at a much lower temperature. Okay - fair enough.

I tried US-05 for the first time on Friday. I boiled just over 100 ml of water and allowed to cool in a sanitized mason jar. It took roughly 90 mins to cool to 76° at room temperature with a piece of aluminum foil placed lightly covering the top. It mixed fairly well, although I could see how the water being warmer could make it easier to mix.

Using this process I had signs of fermentation around 18 hours @ 65°.

 

[boydster]

I'm not saying I'm satisfied, just posting it here for all to be on the same page. From what I can decipher, they have magic on their side. And pure, unadulterated awesome. Who needs to present data when you have that 1-2 combo going for you?

 

[Puddlethumper]

I'm sorry if I'm a cold plug in this discussion but I happen to appreciate the fact that Fermentis responded to the email in the first place.

I happen to be employed in an industry that is rife with second-guessing by outsiders who think they know a lot more than they actually do. The PhD's in their lab coats aren't PR guys trying to sell the public a bill of goods. Most of the time those guys are putting those advanced degrees to work doing really good science that the general public simply doesn't (often can't) comprehend.

The people at Fermentis are probably not all that concerned with providing extensive data to some random home brewer to support what hundreds of thousands of dollar's worth of research has taught them. Especially when some of that information is quite likely proprietary, bought and paid for with those same R&D dollars.

I, for one, am not inclined to second-guess those lab-coats. I've learned to read and follow the manufacturer's label instructions for the products I handle every day. And you know what? When I do that I find I can count on those products' performing exactly as advertised.

 

[boydster]

I don't disagree with you, Puddlethumper, and I also appreciate the fact that they responded finally. The person who wrote back to me isn't in the R&D department though and admitted as much. I actually wrote back asking "let's say I rehydrate 2 brand new packs of US-05; one at 80F and the other at 100F. Which packet would have higher viability?"

From Fermentis:

You can reach our specs on our website (http://www.fermentis.com/wp-content/uploads/2012/02/SFA_S04.pdf). We inform our active dry yeasts contain >6exp9 viable cels/g, following the proposed rehydration protocol. This number is the one you need to consider.

As I told you in your previous e-mail, I don’t know why competitors inform 100 °F is the ideal rehydration temperature. I have two possible explanations: 1) They have never improved the drying process and dried cells are weak to support rehydration at low temperatures (elasticity of the membranes is affected at lower temperatures, thus increasing cellular breakdown) or 2) They have never validated the rehydration al lower temperatures, despite any potential improvement in their technology.

I don’t have any chart showing viability vs rehydration temperatures (I am not part of the R+D). However, the most important for our customers is that we are consistent with the informed specifications. So, any chart is irrelevant in this case. If we inform lower temperatures it is because this is the best rehydration temperature for the yeast concerned.

If you are not yet satisfied with my answer, I invite you to design an experimental protocol and test your hypothesis. Please, be sure you will be using the correct lab techniques.

I guess my only frustration is that I'm asking what should be a simple question and I just wanted a straightforward answer. At least they answered though, and I did send one last request to the rep to see if he would mind forwarding my question to R&D to see if they had a quick and simple answer. It really only makes a difference on big beers - in gravity and/or volume - but I make high OG beers sometimes so I'd like to know. And honestly, that 6x10^9 figure is not exactly a selling point - if each packet really had only 69 billion cells in it after being rehydrated, I wouldn't be using it. Plus, other reps from Fermentis have stated the packets leave the production line with an average of 150 billion cells per 11.5g packet, and independent cell counts from other people have arrived at similar cell counts.

 

[Puddlethumper]

I guess my only frustration is that I'm asking what should be a simple question and I just wanted a straightforward answer.

Sorry if I came off a little harsh. (Spent some time on the phone yesterday with just one of those people I was describing!)

And I do hear you. I've run into similar roadblocks to information in my industry. Fortunately, because we purchase significant quantities of the materials we handle, the manufacturer's reps tend to take my inquiries a little more seriously. As a result I usually end up getting the information I was seeking.

However, it is important that we all realize that if I was a homeowner who picked up an occasional bottle of their consumer-level products I doubt they would provide me with much more information than what they have already published.

Cheers!