Totes.McGoats wrote:I am getting a slight solventy/acidic flavor in my last two batches. I brewed a dry stout and a robust porter all grain. My water is really hard, with lots of chloramine. I run it through a carbon filter and sparge with RO water (don't remember where I heard to do this, but starting to question it's validity) I have a Therminator plate chiller which I clean with hot PBW and water pressure right after I chill, the following day bake it at 350 for an hour and clean it again before I brew. I run Star San (used with distilled water to maintain its effectiveness) thru the whole system for 30 minutes and have my carboy filled all day long. The reason I give my process is I don't know where I could be getting a lacto infection (which is what I think it is) any ideas ?
Let's not jump so quickly to a Lacto infection because that will likely lead to a tunnel-vision approach to the problem which will mask things for future batches. It certainly could be lacto, but don't rule out other parts of your process. Here are somethings I would ask myself if I were in this situation. Hope some of this can help.
1. What were your pH readings during the mash, into the kettle, into the fermentation and post fermentation? Did your RO water lack the proper buffering minerals/capability to keep the darker pH-lowering malts from lowering your pH too far?
2. How long did you mash for and at what temp?
3. Describe your fermentation. What yeast strain were you using, what generation of the yeast strain was it? Is this a new vial/smack pack or has this been rinsed from previous batches? What was your fermentation temp, aeration, pitching rate and pressure/headspace in the fermentation?
4. Pour yourself a sample your beers and smell them next to a commercial Stout or Porter example at room temp to give you a better idea of off flavors and aromas. Now plug your nose and taste your beers. Are your taste buds telling you it's acidic and potentially fusel-like or is your nose the primary indicator of the solvent character?
5. Before focusing on a lactobacillus infection, ask yourself what is a lactobacillus infection, where does it potentially come from and what are indicators of it? Just because there is acidity doesn't necessarily mean there is a bacteria creating that acidity. If you're unable to answer these questions then you may potentially just be guessing at the problem. Focus on what you know to be obviously wrong with the beer and work backwards in your brewing process. Chances are most problems occur prior to, during or after fermentation.
6. Are there potentially fusel alcohols present from fermentation?
7. Is there a large presence of esters in the beer? Ethyl Acetate is a common ester that has a fruity solvent like character.
8. Are you soaking your chiller in PBW for an extended amount of time, multiple times or are you rinsing it with hot PBW once or twice?
9. Bottle 2 or 3 of the beers and let them sit at room temp for a few weeks. If upon opening the beers you seen an increased amount of Diacetyl, CO2/Beer Gushing, Haze, pH Decrease, Lactic Acid, Acetic Acid, Ethanol or other inappropriate off character there's a chance some sort of an infection is at work. If this is the case, toss your hoses and "soft parts" used around the time of fermenting.
10. Have you filtered the beer with gelatin or any other fining agents yet? If so, is/was the flavor there before, after or both?
11. When's the last time you replaced your "soft parts"?
12. What's your method of cleaning your fermentation vessel?