Show Posts

This section allows you to view all posts made by this member. Note that you can only see posts made in areas you currently have access to.


Messages - nateo

Pages: 1 ... 112 113 [114] 115 116 ... 145
1696
Other Fermentables / Re: Acetic acid curiousity question
« on: March 15, 2012, 08:16:28 AM »
I know sulfites will kill the acetobacter with sulfur dioxide (SO2). The sulfur dioxide enters the cells of bacteria and wild yeast and disrupts enzymes. The kinds of yeast winemakers use are more tolerant of SO2 than wild yeasts, but I don't know why. How effective metabisulfite is depends on the pH. Lower pH will result in more molecular SO2 (the kind that can enter the cells).

1697
Other Fermentables / Re: Acid in cider
« on: March 15, 2012, 07:38:27 AM »
Keep in mind pH and titratable acidity are different. Certain acids like malic are perceived as more "sour" than, say, lactic. Malic acid is associated with crisp freshness in fruit. Citric acid isn't too hard to find for canning, and you can probably get malic, tartaric and lactic individually at your LHBS.

1698
General Homebrew Discussion / Re: Batch 500
« on: March 14, 2012, 01:29:00 PM »
Why the need for a glucan rest?  After all isn't one of the signature features of rye or wheat the silky mouthfeel and big body?  I only ask because I recently heard an experience judge say a rye beer needed a glucan rest.

The glucan rest doesn't get rid of all the glucans, just enough to turn it from glue into wort.

1699
General Homebrew Discussion / Re: Batch 500
« on: March 14, 2012, 11:25:56 AM »
Lots of rice hulls! I typically use a pound of them in a wheat beer for a 5 gallon batch.

Stuck sparges aren't as big of a deal as getting a decent crush on my wheat malt. I usually take extra care to condition the barley malt portion, and crush a little coarser than usual to leave the husks as intact as possible. I then have to run the wheat malt through my mill 3 times to get a decent crush. I get about 10% lower efficiency when using a large amount of wheat. If I crush finer to get better efficiency, then I run into slow/stuck sparge issues.

The wheat malt I have is also pretty high in protein and glucans, and is undermodified, so I need to at least do step mashes, and sometimes decoction mashes to get the wort flowing well. It's not a big deal, but it adds a couple hours to the brew day, and leaves me wondering why I don't just buy some malt extract.

1700
this is an interesting idea. However you are only looking at 1 nutrient. Perhaps it would be worthwhile to find a yeast nutrient with low or no N but I have noticed (in a very unscientific way) better results when using nutrients then when not, at least with big beers.

Servomyces and GoFerm (I think) have relatively low nitrogen levels, but I think they still have some. I can't find specifically what they contain, but the descriptions of how they're made sound very similar. I'm completely on-board for having proper yeast nutrition, don't get me wrong. My gut is telling me that yeast nutrients that also contain additional nitrogen and ammonium salts like Fermaid-K wouldn't really be appropriate for wort fermentations, and something like Servo or GoFerm would be better.

In the kind of beer fermentation you'd need additional nutrients (big beers), you probably wouldn't be able to detect vitamin/mineral faults anyway, as long as you didn't add way too much. Without a lot of lab testing, you're just guessing if your wort needs extra nutrients or not. I "just guess" on a lot of brewing-related issues, like yeast counts and AA% for my hops, so I don't know why this makes me uneasy.

As an aside, I've read that winemakers that don't like to deal with formol titration to determine nitrogen levels just use their nose, and add nutrients if the yeast starts throwing sulfur. 

1701
The more I think about it, the less adding nitrogen to beer fermentation makes sense to me. I haven't found many hard numbers for yeast available nitrogen content in wort, but one study found a typical range to be 1-2g/L, or 1000mg/L - 2000mg/L.

Brewers' yeasts' nitrogen requirements aren't published, but wine yeasts' are. The "standard" winemaking yeast available nitrogen recommendation at 28 Brix (1.120) would be 375-425mg/L. Wine yeast nitrogen requirements vary pretty widely, with some needing nearly twice as much as others. I assume beer yeasts are similar in that regard. Even if the yeast needed twice the nitrogen, that'd only be 850mg/L, well below the minimum reported amount of yeast available nitrogen in wort.

In order to need nitrogen for a wort fermentation, you'd need to have a very nitrogen-deficient wort, and a yeast with exceptionally high nitrogen needs.

EDIT: Thanks MX, fixed it. Nitrogen =/= nutrients.

1702
General Homebrew Discussion / Re: Batch 500
« on: March 14, 2012, 06:55:54 AM »
I really love wheat beers, but I hate brewing with wheat. Milling it is a PITA, and stuck sparges are a PITA. I'm thinking about going back to extract for my wheats just so I don't have to deal with it. Before I switched to AG, though, I made some great wheats with wheat LME.

1703
Yeast and Fermentation / Why does acidity impair yeast performance?
« on: March 13, 2012, 05:07:42 PM »
I think it has something to do with the H+ ions disrupting proton ATPase, and secondary active transport, but I only have a fuzzy (at best) understanding of microbiology.

1704
I would be incredibly careful adding nutrients, if you do. Wort has a really high level of yeast available nitrogen (relative to any other growth medium). Too much nutrient will cause off-flavors, and if you add too much at the wrong time and the yeast can't use it all, it could potentially feed bacteria.

Adding O2 multiple times keeps the yeast in growth mode. They make like 33x more alcohol per cell during the growth phase than during the stationary phase. This is related to incremental feeding of nitrogen, but again, be careful not to overdo it.

1705
I have always wondered about the whole incremental feeding thing, not understanding how it helps to feed incrementally when the net effect is the same level of alcohol. But if it's an issue of osmotic presure that makes sense to me. as the gravity goes down you can add more sugar without exceeding the presure threshold! thanks nateo!

Whether or not osmotic pressure matters really depends on the health of the cell walls, but even healthy cells have trouble over 1.120. I've read (don't remember where) that osmotic pressure inhibits fermentation even down at like 1.060 if the yeast have poor cell membranes. The pressure will literally squeeze nutrients out of the yeast, like squeezing a wet sponge, only instead of water, nitrogen comes out, inhibiting their fermentation performance.

1706
All Grain Brewing / Re: multi-batch, combined fermentation question
« on: March 13, 2012, 09:58:32 AM »
AFAIK, the main reason pro brewers do what you're talking about is that it simplifies yeast propagation. It's easier to grown enough yeast for 1bbl than 10bbl.

I don't see any particular problem with this. I'm a big fan of incremental feeding in general. I wouldn't aerate the subsequent wort you add. The yeast should be done growing by then.

I'm also time-poor, since I have to work 12+ hours a day, almost every day. I'm considering going back to extract and steeping grains just to get more brewing done.

1707
I would consider doing incremental feedings. Osmotic pressure starts to be an issue around 1.120.

If I were going to brew a beer that big, I'd start it at whatever OG I could easily get, let it ferment a good bit, then add malt extract to make up the difference in gravity. It will be kinder for your yeast and easier to achieve.

I would also use a good amount of simple sugar, maybe 10-15% of fermentables. Attenuation is going to be your biggest issue with a beer like that.

Here's the link Hopfen was talking about. That page was a godsend when I started making bigger beers. Before I found that my big beers sucked.
http://beerdujour.com/Howtobrewabigbeer.htm

1708
General Homebrew Discussion / Re: Batch 500
« on: March 13, 2012, 07:00:47 AM »
have you malted your own grain yet? what about growing it? there is no last big step. it just keeps going. up and I don't know where it's going to stop!!!!

[Public Service Announcement]

As a chronic sufferer of of YDIW, I struggle with my disease every day. YDIW is a social-skills disorder that Internet forum members are at heightened risk of developing. Others at heightened risk include religious fundamentalists, sports fans, and advice columnists. The only known treatment for YDIW is "No one cares what you think!" It should be applied liberally whenever YDIW flares up.

I don't ask for you pity, only your understanding. Together, we can beat YDIW!

[end transmission]

1709
Going Pro / Re: Looking into starting a meadery
« on: March 12, 2012, 03:17:39 PM »
I contacted the Missouri Wine Advisory Board. They weren't helpful. I got ahold of someone at the main office for the state Alcohol Control division, and he was really helpful. That guy said that it's the position of his agency that statutes take precedent over regulations, and that if state law says I can use honey in my winery, then it doesn't matter if the regulations don't specifically state that I can.

He also told me that my county health inspector is the one who will actually be inspecting the facility, and as long as they're happy with the facility, the state is happy. It seems like the state doesn't particularly care about regulating. Yay, Missouri!

1710
Equipment and Software / Re: Food-grade buckets at Lowes
« on: March 12, 2012, 11:09:04 AM »
I brew 3 gallon batches also, perhaps I should look into these here buckets.  I'd probably have to drill out the lid though for an airlock...hmmmmm.

My LHBS in Colorado had lids that were predrilled and grommeted. The LHBS here just drills a hole in the lid for you, and they have little rubber stoppers for it. Not quite as elegant as the grommet, but it works fine and is easy to clean.

Pages: 1 ... 112 113 [114] 115 116 ... 145