Rennet loses potency

[johnr]

Hi

I am new to making cheese and purchased veal rennet approx 1.5 months ago.  Since I purchased the rennet, I noticed that I either lose the cheese batch or I let it sit twice as long to really give me a clean cut.  I was chucking these issues to me being new. Today before I started a new batch I decided to test my rennet.

I ran two different tests and flocculation happened about 2 times later than expected.  I had to almost double the rennet to get to flocculate when it was supposed to.  So.... I decided to do just that with my batch of cheese today and flocculation was achieved at 11 minutes which is what it should have always been according to the recipes I use.

My question is how do I make sure that when I buy rennet, I don't get an old bottle?.  I have contacted the seller, pretty famous seller, and complained about the rennet.  But how do I know where to buy rennet that is not already weak by the time I get it?

Also, am I supposed to run through a flocculation test every time I am going to make cheese?.  If I have to titrate it will be difficult to know exactly how much I need to pad it to.

Thanks

Thanks

[Kern]

You didn't say exactly how you are using the rennet.  Here is what you should be doing:  The rennet should have been put in the refrigerator when received and should be stored there.  The rennet should be diluted in cool non-chlorinated water no more than 2 minutes before being added to the cheese milk.  The water should have a pH around 6.5 of a bit less.  So check the pH of the water you are using.  Some distilled water now contains ozone to preserve freshness.  I always boil the water I dilute rennet and calcium chloride.  This will get rid of chlorine as well as ozone.  I add a couple of drops of P&H milk to the water as it boils.  If your water has a pH above 6.5 add one drop of vinegar (acetic acid) per cup of water to acidify it.

If doing all this fails to solve the problem then you likely have old rennet.   

[johnr]

I have kept the rennet in the fridge the entire time.  I only use RO water I make and I use it within 2 to 3 minutes after mixing.  My RO water is around 6.0 ph.

Thanks

[Kern]

It sounds like you have a rennet problem.   

[johnr]

I thought so.  So being that I bought from perhaps one of the most popular places, what should one do to ensure that the rennet is healthy and how long can I expected to last?

Thanks

[Kern]

Well you didn't say where you bought the rennet.  But, I don't conflate popularity with quality.  I personally like the Dairy Connection.  http://www.dairyconnection.com/  These guys supply the commercial cheesemaking industry in Wisconsin but have a consumer division.  To be fair to your source, though, it is possible that the bottle was contaminated.   

[johnr]

I just ordered from them.  Kern, do you cut your curds with a knife or a curd cutter?.  I do 2 gallon batches for now.

Thanks

[Kern]

My cheese makes are all in vats.  See http://cheeseforum.org/forum/index.php/topic,14584.msg110860.html#new.  The curd cutters I use come from Perfect Cheese http://www.perfect-cheese.com/.  You'll see in one of the photos I posted how I adapted the six inch cutter to do an eight inch tank.  You'll find an excellently designed cutter by Spoons at http://cheeseforum.org/forum/index.php/topic,12157.0.html .  I've already purchased some of the 1/2 inch strips Spoons mentions and will be making a cutter next week.  I am a big believer in good curd cutting as it affects ultimate moisture content.  Other than the Perfect Cheese cutters (great on 6-inch vats) there is not much out there besides a knife.