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Forced Wort / Wort Stability Test

Post #1 made 12 years ago
by BrickBrewHaus
Over the past couple of days I've heard/read about forced wort tests twice (once while listening to a Brewing Network podcast, and today in the latest issue of BYO). I'm thinking its the brewing gods telling me I should look into it...

Has anyone ever done this? Can you give your experience and tips?

Here's what I'm thinking
-I don't really know what to look for. In the little bit of research I've done, a sample, if contaminated, will turn cloudy around 72hrs after chilling. "Cloudy" is a bit ambiguous so...
-I could do a trial run. Boil up some light DME in an Ehrlenmyer. Then prepare a few containers to incubate the wort. One will be a babyfood jar that has been sanitized in boiling water. The other will be sanitized with star san. The last won't be cleaned and allowed to sit uncovered for some time to accumulate some nasties.
-By boiling/chilling the wort in an Ehrlenmyer, I'm stacking the deck to produce clean wort on that end. Then the variables will be the cleanliness of the jars.
-Hopefully I will see that the boiled jar stays "clear" for at least a week and the uncleaned jar becomes "cloudy" much sooner (2 days?). This will give me a good idea of what I should be looking for.

Once I have a handle on what to look for in a positive test, then this could be a simple thing to do once and a while to test my sanitation pre-fermentation.
Last edited by BrickBrewHaus on 19 Dec 2011, 21:42, edited 1 time in total.

Post #2 made 12 years ago
by stux
Not sure about "Forced Wort Test" but I sometimes do "Forced Ferments"

The easiest way is to take a gravity sample from the fermenter just before pitching yeast from a decanted starter flask. Pitch the yeast, then drain the dregs into the hydro sample jar and cover with tin foil.

The foil helps prevent wild contamination, and the dregs should be plenty potent to get the yeast a kick off. Best to keep the hydro sample in a warm place... say in doors etc.

It should finish fermenting before the main batch, and you can rouse it at your pleasure etc to see how low the batch should go if everything is going good.

Also, if you just draw off a hydro sample a day or two into fermentation and keep that then it should be just as good. The key is to keep it warmer than the main ferment so that it finishes faster.

Invariably, I end up needing my hydro jar back and that's when I end up tossing the sample ;)
Fermenting: -
Cubed: -
Stirplate: -
On Tap: NS Summer Ale III (WY1272), Landlord III (WY1469), Fighter's 70/- II (WY1272), Roast Porter (WY1028), Cider, Soda
Next: Munich Helles III

5/7/12

Post #3 made 12 years ago
by BrickBrewHaus
Forced fermentation isn't quite the same thing. It looks at the fermentability of the wort and allows you to compare the FG of the forced ferment sample to your beer and see if there are any short-comings in the pitch rate/oxygen/etc. that prevents your beer from fully attenuating.

A forced wort test, or wort stability test (changed in the title of the thread), tests your sanitation practices by encouraging bacterial growth. If you don't see any signs of growth after 3 days, the general consensus is that your sanitation practices are good.

Here are a few good links:
BYO article
Wyeast
Brewing Science
Last edited by BrickBrewHaus on 19 Dec 2011, 21:55, edited 3 times in total.

Post #4 made 12 years ago
by joshua
Good Day, I checked with a few 'Old Timers', and the forced wort tests(f.w.t.) are used to finding problems from the wort, as well as the fermenter, if the fermenter goes bad and the F.W.T. is good, you can find where the problems is.
Now, if you take a liter/quart of fresh wort, keep it covered, and nothing happens, the wort can be used as wort added to the cleared beer for Carbonation. The wort can also be used as a starter for the next batch.
Of course, if the F.W.T goes bad, your fermentation may be bad, and you toss the whole batch away.
The only thing I can see the F.W.T. is good for is a starter.
Honest Officer, I swear to Drunk, I am Not God.
    • SVA Brewer With Over 100 Brews From United States of America

Post #5 made 12 years ago
by BrickBrewHaus
I may be wrong here, but I would be reluctant to completely agree with these statements.
joshua wrote:Now, if you take a liter/quart of fresh wort, keep it covered, and nothing happens, the wort can be used as wort added to the cleared beer for Carbonation. The wort can also be used as a starter for the next batch.
No brewer, especially homebrewers, works under sterile conditions. Therefore, by definition, there are some bugs present in our beer. By doing the f.w.t., the brewer is storing the sample at temperatures that deliberately encourage the growth and propagation of these bugs. So even if the test results indicate that your brewing practices are reasonably sanitary, wort clouds AFTER 3 days or more, the level of contamination has grown to an amount that I wouldn't feel comfortable putting back into "clean" beer.
joshua wrote:Of course, if the F.W.T goes bad, your fermentation may be bad, and you toss the whole batch away.
The only thing I can see the F.W.T. is good for is a starter.
I guess this begs the question, "What is a "bad" result?" I doubt there will be clear, black and white answer here. Rather, more like a continuum. I doubt that I'll find myself throwing out a batch of beer based solely on the result of a f.w.t. In my opinion, its an indication of cleanliness, but there are other things (like placing the wort sample in a sanitary container) that could give a false positive.
Last edited by BrickBrewHaus on 20 Dec 2011, 00:05, edited 3 times in total.

Post #6 made 12 years ago
by joshua
Good Day, I have made two batches of tart lemon candy flavored beer, it look good as a bown porter, had a good head, Traced it to black poop in the valve of the bottling tank.
The F.W.T is only one place to check for contamination. For me...F.W.T. is Fully Wasting Time. But for others testing, testing, and more testing is wanted.
Honest Officer, I swear to Drunk, I am Not God.
    • SVA Brewer With Over 100 Brews From United States of America

Post #7 made 12 years ago
by BrickBrewHaus
joshua wrote:For me...F.W.T. is Fully Wasting Time.
I have a hard time believing that anything sanitation related is a full waste of time. I like experimenting and I'm concerned with monitoring sanitation, especially for the small amount of additional work required.

So anyone else have experience?
Last edited by BrickBrewHaus on 20 Dec 2011, 01:17, edited 3 times in total.

Post #8 made 12 years ago
by joshua
Good Day, Testing is the waste of time, If you know about sanitation and cleaning, Testing everything really doesn't help. As I wrote before, the plastic valve had the infection....The valve is gone, the hole is sealed, and my siphon now has a bottling valve. The less equipment means less cleaning, less sanititon, and many less problems. Test all you want, You will probably miss something.
If I made 15BBL a day, I would test EVERYTHING. 15bbl is too much to waste. But for 1/12 bbl, pouring it out is not a problem.
Test all you want, It is a good Practice...For Me, it is a waste of time
Honest Officer, I swear to Drunk, I am Not God.
    • SVA Brewer With Over 100 Brews From United States of America

Post #9 made 12 years ago
by stux
So, my 9 month no chill passes :)

I also did a three step starter the other day from my recovered wort

.5L 1L 1.5L

I prepared all three flasks at once and left the last two simply sealed for about a week. No activity :)
Fermenting: -
Cubed: -
Stirplate: -
On Tap: NS Summer Ale III (WY1272), Landlord III (WY1469), Fighter's 70/- II (WY1272), Roast Porter (WY1028), Cider, Soda
Next: Munich Helles III

5/7/12

Post #10 made 12 years ago
by Ziggybrew
Highly recommending the book, "YEAST, The Practical Guide to Beer Fermentation", by Chris White (of White Labs) and Jamil Zainasheff. Page 220 starts an in-depth discussion on Forced Wort Testing. This book is amazing, but I've had to read it several times to let everything sink in... sorta. :scratch:
But yea, I agree with you. Unless there is hundreds of thousands of dollars at stake -- skip doing this. Time would be better spent just reading this brewing masterpiece.
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