Chemical Taste Plaguing My Brewery

[wbosher]

I only thought so because you can't microwave baby food.

Really? I microwaved both of my kids baby food when they were little. Sorry, getting a little OT.

 

[manticle]

Just a thought and I don't know for certain but I would have to say that microwaving gelatin might possibly denature it.
I only thought so because you can't microwave baby food.
Try just boiling your water then adding the gelatin when it's cooled to 70 degrees or less.
Worth a try if your method isn't clearing the beer.

I'm pretty sure Gelatin starts to denature way below 70 degrees - closer to 35-40.

^

Actually just trying to find a reference for this and now I'm not so sure. Collagen denatures around human blood temperature and gelatin liquefies somewhere around there but denaturing might be higher. I would have thought the information would be easier to find. Maybe I'm looking in the wrong place.

Boiling will destroy some of its properties though.

 

[krausenhaus]

I'm just following the method that I think is in one of the wikis here and a lot of other people seem to use. I don't microwave it to boiling, just a couple of 20-30 sec bursts until its hot and dissolved.

As you can see from the photo, it's not really an issue of the gelatin being ineffective at clearing the beer. The gelatined beer is coming out cloudier than the untreated beer, and tasting and smelling contaminated, so something else is going on.

I've taken a bunch of samples that I'm going to try and culture, with a grain of salt though as it wasn't the most sterile process. Good idea on the anaerobic plates Nev - the problem is only occurring in finished beer with no dissolved O2. Hopefully I can find someone to let me use a chamber somewhere.

 

[pcmfisher]

You tasted gelatin and water and it tasted ok? :huh:

 

[Thefatdoghead]

Really? I microwaved both of my kids baby food when they were little. Sorry, getting a little OT.

That's why they make money on bottle Warmers. The baby food tin does say not to microwave as well.

Sorry for off topic.

 

[mje1980]

Is the brewbrite old?

 

[yum beer]

Why not try mixing your gelatine the old school way in same tepid water and stir till dissolved.
Seems a good chance your current process isn't working...can't imagine the microwave is a good idea.

 

[drsmurto]

I'm just following the method that I think is in one of the wikis here and a lot of other people seem to use. I don't microwave it to boiling, just a couple of 20-30 sec bursts until its hot and dissolved.

As you can see from the photo, it's not really an issue of the gelatin being ineffective at clearing the beer. The gelatined beer is coming out cloudier than the untreated beer, and tasting and smelling contaminated, so something else is going on.

I've taken a bunch of samples that I'm going to try and culture, with a grain of salt though as it wasn't the most sterile process. Good idea on the anaerobic plates Nev - the problem is only occurring in finished beer with no dissolved O2. Hopefully I can find someone to let me use a chamber somewhere.

Plastic is oxygen permeable and a few squirts of CO2 will not displace all of the O2 in the headspace. I routinely measure oxygen both dissolved and also headspace oxygen and it takes several minutes of high pressure gas (I use nitrogen) to displace all the oxygen. Not that I think this is your problem, just clearing up an urban myth. EDIT - I do this at work in the lab just in case someone thought I have a DO meter in the brewery. Oxygen levels are a critical measure to understanding the area I am researching.

You have stated you don't think it is due to the jerry cans you use but what have you don't to show it isn't? QldKev suggested a very thorough way of showing this one way or the other.

Cloudy finished beer, assuming you aren't using a strain of yeast that is notoriously difficult to clear and assuming you are allowing time post FG for the yeast to finish and flocculate, says infection to me. More so when it doesn't appear to be all the time but is in some beers but not others. Could be the gelatine itself that is harbouring a bug but it's more likely something in your jerries or air-borne. 1C is not going to stop an infection, it will only slow it down.

If I was in your situation I would be nuking all the plastic containers you use - fermenters, jerries, cubes etc with bleach. Throw in your hoses as well. It is always a good idea to switch up your sanitation regime to keep any resident bugs on their toes. They are very clever little things that can evolve to get used to their environment.

 

[krausenhaus]

Plastic is oxygen permeable and a few squirts of CO2 will not displace all of the O2 in the headspace. I routinely measure oxygen both dissolved and also headspace oxygen and it takes several minutes of high pressure gas (I use nitrogen) to displace all the oxygen. Not that I think this is your problem, just clearing up an urban myth.

What I was really getting at is that the DO levels in my finished beer would likely be too low to prevent a strict anaerobe from growing, and if it is an anaerobic contaminant then I'm not going to find it on aerobically incubated plates.

You have stated you don't think it is due to the jerry cans you use but what have you don't to show it isn't? QldKev suggested a very thorough way of showing this one way or the other.

My jerry cans are of varying ages, and this is a recent problem. In the batch that it has just occured in, they were in new ones, and it only happened in one of them. Before I racked the beer into them I gave them a good soak with hot water followed by a couple of rinsings, and tasted the last lot of water to come out.

The taste only occurs in fermentors that have been gelatined and cold crashed. Up until that point, they're fine, and have been sitting in the jerry cans for 2-3 weeks.

 

[kixbooty]

Why not try mixing your gelatine the old school way in same tepid water and stir till dissolved.
Seems a good chance your current process isn't working...can't imagine the microwave is a good idea.

Yeah, and the microwave is probably not the cleanest. I haven't cleaned it in months. And I have seen that program "How clean is your house?" where they do a swab test on a microwave and it has a zillion bacteria.

Hopefully the samples krausenhaus took today tell us something.

 

[HBHB]

Both Glycine and Lysine, which are amongst the components of gelatine are capable of releasing funky flavours if microwaved as it breaks these amino acids down (de-nature them if you like)even for short periods of time.

Gelatine can do the same thing if allowed to sit at near boiling temperatures for too long. Thus, the best way to dissolve your gelatine is to use pre-boiled water which is allowed to cool to a warm/hot temperature - as soon as it's dissolved, drizzling it into your beer will stop the further breakdown.

Martin

 

[micblair]

1. Use irish moss or some other carrageenan based finning. Whilst PVPP/brewbrite is food safe and a common fining in the beer and wine industry, putting plastic in beer no matter how effective, isn't cool.

2. invest in a chiller and pitch the yeast while the wort is fresh!

3. Switch to a glass carboy, plastic fermenters wear out.

4. To pasteurise the gelatin (I use McKenzie brand) at 70C for 10 mins, and I think it is the bomb. If you combine it with a cold crash, commercial level of brightness in 5 days at near zero is easily achievable.

 

[manticle]

Both Glycine and Lysine, which are amongst the components of gelatine are capable of releasing funky flavours if microwaved as it breaks these amino acids down (de-nature them if you like)even for short periods of time.

Gelatine can do the same thing if allowed to sit at near boiling temperatures for too long. Thus, the best way to dissolve your gelatine is to use pre-boiled water which is allowed to cool to a warm/hot temperature - as soon as it's dissolved, drizzling it into your beer will stop the further breakdown.

Martin

Interesting. Any idea if the funky flavours are close to what krausen describes?

 

[Online Brewing Supplies]

shouldn't it taste like cow hoof ?
Nev

 

[HBHB]

Interesting. Any idea if the funky flavours are close to what krausen describes?

Difficult thing with amino acids manticle. We had one of the local brewers with a similar issue going back 12 months or so ago. At the end of the day, the only thing changed was the process of microwaving the gelatine and "voila", the issue went away. What he was getting was a kind of plastic / chemical like taste. I'd describe it as that plastic chemical taste you get every now and then in homebrand icecreams. As i'm sure you'd know, It can be hard to track and pinpoint some flavours. Without experiencing the same flavour, i'd be at a loss to say "That's it" but it's another possibility.

It can be so hard to track these things with so many process control points that can be altered from one brew or another. Ended up going to one guy's home one day after 2 months of going through what his process was. Had to sample some of the worst beers imaginable over that time. Trust me when I say this, 200 odd home visits a year to help guys with brews and you get to taste the odd wild brew. Ended up being the 15 yr old garden hose he forgot to mention in a dozen visits. "from the tap" isn't the same as "from the hose". uke:

Martin

 

[manticle]

It sounds spot on to me and I know the flavour you mean in cheap icecream.

Interested to see if you've nailed it.

 

[krausenhaus]

I didn't always microwave the gelatine - I used to do the warm water method until I saw a lot of people in the 'How-to' thread talking about microwaving and thought it'd be a little more sanitary.


And casting my mind back, this problem started occuring around the same time as I changed technique.

We may well have found the problem here. Thanks a lot, guys. I'm off to go beat my head against a wall for ruining 100+ litres of beer and wasting a lot of time and money.

 

[Online Brewing Supplies]

Does it explain the cloudy wort ??
Nev

 

[treefiddy]

Both Glycine and Lysine, which are amongst the components of gelatine are capable of releasing funky flavours if microwaved as it breaks these amino acids down (de-nature them if you like)even for short periods of time.

Gelatine can do the same thing if allowed to sit at near boiling temperatures for too long. Thus, the best way to dissolve your gelatine is to use pre-boiled water which is allowed to cool to a warm/hot temperature - as soon as it's dissolved, drizzling it into your beer will stop the further breakdown.

Martin

Actually gelatine is denatured collagen. You can't denature gelatin, but you can hydrolyse it.
To denature is to remove the structure (shape). Hydrolysis is what breaks down gelatine (a polypeptide) into amino acids (glycine etc) and then further again. You can perform hydrolysis in a microwave, but you need acid also.

If I get yeast that just will not drop, I boil some water in a flask, let it cool for a few minutes so its easier to handle and add gelatine (1 tsp per 100 ml per keg). Give it a good stir/swirl to dissolve and then let it cool (covered) until I get around to using it.

Works well for me.

 

[krausenhaus]

Hydrolysis is what breaks down gelatine (a polypeptide) into amino acids (glycine etc) and then further again. You can perform hydrolysis in a microwave, but you need acid also.

Really good point. Microwaving in water for 40-60 seconds is not going to hydrolyse any peptides. I wonder what the hell is going on then.

I am going to take some samples of beer from the good fermentor and add gelatin that has had the microwave treatment to one, gelatin by the warm water method in another, repeats with a different brand of gelatin, and a control. Hopefully this will let me identify the culprit.

If I can replicate the taste, I'll spin that sample down and plate it in case it's an infection being picked up somewhere.