[tschmidlin]

I've had good luck with Bru'n water, so as long as your starting profile is reasonably accurate you should be fine.

I've got nothing else right now.  It's possible that the genome is unstable over that many generations and your fermentation conditions.  I can't say for sure.

[a10t2]

If you don't want the expense and maintenance of a meter, for the $20 investment, I think the ColorpHast strips are well worth it. They are inaccurate in a mash (add 0.3), but consistently precise. I'm with Tom - having trouble with the darker beers makes it sound like a pH issue.

Also, I don't think it has anything to do with the fermentation issue, but there's no need to add magnesium beyond what's contributed by the malt. Unless you're brewing with a large proportion of adjuncts, the wort will already contain >100 ppm Mg.

[morticaixavier]

If you don't want the expense and maintenance of a meter, for the $20 investment, I think the ColorpHast strips are well worth it. They are inaccurate in a mash (add 0.3), but consistently precise. I'm with Tom - having trouble with the darker beers makes it sound like a pH issue.

Also, I don't think it has anything to do with the fermentation issue, but there's no need to add magnesium beyond what's contributed by the malt. Unless you're brewing with a large proportion of adjuncts, the wort will already contain >100 ppm Mg.

I will start by saying that I don't have a pH meter and don't use strips. Like skyler I depend on the accuracy of Bru'n water, although I do start with 100% RO so I don't have to worry about chlorine.

Okay after that very long disclaimer what I was going to say is that there is another thread going right now about pH meters and it looks like you can get one that works well enough for around $20.00.

[blatz]

but there's no need to add magnesium beyond what's contributed by the malt. Unless you're brewing with a large proportion of adjuncts, the wort will already contain >100 ppm Mg.

so no need to add Epsom?  if so, good.

Skyler - interesting observations.  

[beersk]

but there's no need to add magnesium beyond what's contributed by the malt. Unless you're brewing with a large proportion of adjuncts, the wort will already contain >100 ppm Mg.

so no need to add Epsom?  if so, good.

Right, I add epsom for a lot of my beers.

[wildknight]

Right, I add epsom for a lot of my beers.
[/quote]

Why do you magnesium sulfate to your beers?

[morticaixavier]

Right, I add epsom for a lot of my beers.

Why do you magnesium sulfate to your beers?
[/quote]

Yeast require a small amount of Mg for optimum health (and floculation? someone will check me on that) so if you are making an all grain batch and using water deficient in Mg they the idea is you can add it via Epsom salts. However the grain itself (may) have enough in most situations

[a10t2]

if you are making an all grain batch and using water deficient in Mg they the idea is you can add it via Epsom salts. However the grain itself (may) have enough in most situations

The real question is whether the amount contributed by the water makes any difference at all. An all-malt wort will already have about 100-200 ppm Mg, depending on the malt(s). So is adding, say, 10 ppm via the mash liquor going to have any effect?

[tubercle]

That's pretty much how I arrived at my "house" yeast more than 20  years ago.  I took the yeast I started with (an unknown mix to begin with) through something like 15 generations (and actually, probably more than that) and liked what I was getting,  so I banked it.  
To this day I don't know what it actually is or what I isolated when I saved it  (and it really doesn't matter), but it still works great and I use it for the majority of the beer I make.  Occasionally I'll switch off to some London Ale or Old Newark for a few batches, but my old standby is still my favorite.  

 I got one of those Its about time to dig Frankie out of the back of the fridge so it can come out and play for awhile.

 I have no clue how many generations it has been through but it performs every single time.

[tschmidlin]

if you are making an all grain batch and using water deficient in Mg they the idea is you can add it via Epsom salts. However the grain itself (may) have enough in most situations

The real question is whether the amount contributed by the water makes any difference at all. An all-malt wort will already have about 100-200 ppm Mg, depending on the malt(s). So is adding, say, 10 ppm via the mash liquor going to have any effect?

Well, you could add SO4 without adding more calcium, so there's that.  That's the only time I use epsom salts.

[a10t2]

Well, you could add SO4 without adding more calcium, so there's that.  That's the only time I use epsom salts.

I'm not sure I buy that either, frankly. The hardness contributed in order to add a given amount of SO4 is about the same whether CaSO4 or MgSO4 is used. Is there a reason why adding magnesium over calcium would be preferable? I've heard plenty of recommendations for a minimum [Ca], but I don't think there's any consensus on a maximum.

[wingnut]

I am wondering if the cold crash may be causing the yeast to express some tendancies after many generations... (kind of grasping at straws)

One other idea I had was to listin to the Can You Brew It podcast programs with Rouge ale beers featured.  They do pretty good brewer interviews on that show...and I think they talked a lot about how they treat the yeast from batch to batch.  You may be able to get some info on how many generations the brewery tends to use the yeast, and what they are looking for when choosing to go with a new pitch instead of a re-pitch.  They may even go into their re-pitching practices on that one. (if i recall correctly).  Hopefully , with a little time invested in listening to the program, you can get some other ideas on what may be the root of the drift.

Good luck

[tygo]

I am wondering if the cold crash may be causing the yeast to express some tendancies after many generations... (kind of grasping at straws)

I remember a brew strong episode (can't remember which one) where JZ said something to this effect.  That rapid cold crashing would cause the yeast to express some shock proteins which wouldn't affect the current beer but my have an effect if repitching.

[skyler]

I have really just built my waters following the "Yellow balanced, Dark Malty, etc..." profiles since I started using Bru'n Water. The one thing I noticed is that with Bru'n Water, my malty beers are softer and my bitter beers have been less bitter... so I think I will be increasing the salt level the next time I brew an IPA or pale ale. But frankly, the beer quality (and clarity) has increased greatly since I started using these profiles. I sure would like it if something like Bru'n Water was built into the next version of Beer Alchemy.

I recall reading somewhere that John Meier recommended going no more than 6 generations with the Pacman. The lower attenuation could be the reason. the funny thing is that I massively missed my 154 mash temp with the porter (and mashed at 150), and was really upset that the beer would dry out too much. Thankfully, the 5th-generation pacman only fermented down 75% AA despite the low mash temp so I still had some decent body to my porter.

[tschmidlin]

Well, you could add SO4 without adding more calcium, so there's that.  That's the only time I use epsom salts.

I'm not sure I buy that either, frankly. The hardness contributed in order to add a given amount of SO4 is about the same whether CaSO4 or MgSO4 is used. Is there a reason why adding magnesium over calcium would be preferable? I've heard plenty of recommendations for a minimum [Ca], but I don't think there's any consensus on a maximum.

We're pushing the limits of my water chemistry knowledge, but the Net Mash Acidity goes up a lot more per gram of MgSO4 than per gram of CaSO4 according to Bru'N water.  So if I'm trying to add SO4, I get less of a pH drop from MgSO4 than CaSO4.  Possibly because MgSO4 is more hydrated (MgSO4·7H2O) than the gypsum (CaSO4·2H2O), but that's not the whole story if you look at the ppm too.  Someone else will have to explain why it does that, or I'll have to look at it when it's not midnight on a Saturday.   But if you play with the additions in Bru'N water you don't get the same effect by adding the same amounts.