Starter and stir plate problems....

[Homebrewcrazy]

Guy's,

I'm in desperate need of your expertise on starters and stir plates.

I have been all grain brewing for almost two years, and to date have never had a partially fermented beer. I have always used just Wyeast smack packs and never had a problem. Just recently, I started making starters using the smack packs and combining that with a stir plate. My starters consisted of 2 pints of water to 6oz of DME in a beaker and one Wyeast smack pack for approx 24 hrs prior to pitching. The first batch I tryed this on started with a 1.065 gravity and finished with a 1.030. I chalked it up to faulty yeast and went on to my next batch, which I prepared the starters in the same mannor. Well once again 1.060 starting gravity and a 1.030 finished gravity... First and foremost, "WHAT AM I DOING WRONG"? Second, can I re-pitch yeast to activate the fermentation process again after the primary fermentation has been completed


Please help as I am ready to give up with starters and stir plates and just go back to using a smackpack...

Thanks,
Frank

 

[PintOfBitter]

I can't think of any possible reason your stirplate starters could be doing this to you. what are your fermentation temps? are you using any water modifications? what kinds of recipes?

Your yeast may be cranky or flocc'ing too quickly.

 

[Homebrewcrazy]

I may have just stumbled onto my problem. It may have nothing to do with my yeast and everything to do with a my thermometor I am using when taking strike and sparge water temps... I just realized it could be off by 10-12 degree's, making my mash tun temp 165-167 rather than 155 and my sparge water 185-187 rather than 175.. Do you think this could do it?? Maybe I'm extracting unfermentable sugars at these temps??

 

[ajf]

The only thing that strikes me as wrong is the ratio of water to DME that you are using for the starter. For 2 pints water, you need approximately 3.5 oz DME which will give you an OG of about 1.040. 6 oz will gave you an OG of about 1.070 which is going to shock the yeast and prevent the starter working properly.
Another possible cause of problems it the temperature at which you made the starter.
For an ale yeast, you want to keep it at about 70 - 75F. Cooler temperatures slow the starter down considerably, and you may need to keep the starter going for 2 - 3 days before it's ready.

Hope this helps. Don't give up on the starters. I have found that they help tremendously with improved attenuation and reduced lag time.

Edit.
Yes, if your thermometer is off by that amount, it will have a big effect on attenuation.

-a.

 

[RiverCityBrewer]

I may have just stumbled onto my problem. It may have nothing to do with my yeast and everything to do with a my thermometor I am using when taking strike and sparge water temps... I just realized it could be off by 10-12 degree's, making my mash tun temp 165-167 rather than 155 and my sparge water 185-187 rather than 175.. Do you think this could do it?? Maybe I'm extracting unfermentable sugars at these temps??

I think that could definitely be your problem... higher mash temps make for less fermentables, however, I don't know if would make it that bad. Are you aerating/oxygenating your wort well? What about batch size? Any yeast nutrients added to starter/wort?

 

[Homebrewcrazy]

Thanks guy's I'll adjust my starter DME/Water volume as per your suggestion.

I am still wondering at what temp you start extracting Dextrins or unfermentable sugars from the grain, I may have a faulty thermometor and It may have caused me to mash at 168 and sparge at 185??

With all the money I've spent on high tech equipment, stir plates CFC and pumps I am still using a $6 thermometor... Deserves me right if this is the problem.

Thanks,
Frank

 

[Homebrewcrazy]

I think that could definitely be your problem... higher mash temps make for less fermentables, however, I don't know if would make it that bad. Are you aerating/oxygenating your wort well? What about batch size? Any yeast nutrients added to starter/wort?

I'm oxyenating the wort with pure O2 and then shaking it after pitching to make sure... I am making ten gallon batches and splitting it into two fermentors.

 

[RiverCityBrewer]

Sounds like your process is good, seems to me that the culprit may be the faulty thermometer.