Author Topic: testing rennet?  (Read 417 times)

Offline Salilah

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testing rennet?
« on: March 30, 2013, 02:57:47 AM »
Further to my recent posts on somewhat soggy cheese - is there an easy way to test if rennet is any good?

Last weekend I threw away my goats milk after it hardly set at all - it was like single cream
This weekend I tried again with non-homogenised milk using the Caldwell camembert recipe (which I've done before)
The setting time was 30-35mins
After 30mins, nothing; same at 45m; same at 60m; same at 90m! 
I got annoyed and added 5 drops of my old non-animal rennet (expiry date passed) and got a good set in about 20mins!

I'm guessing my newer (animal) rennet may be either poor, or I'm not using enough?
The bottle says one drop per litre of milk - does that sound right?
If yes, how can I test it? (before I go back to the guy who sold it to me and ask politely for a replacement!)

thanks lots
S


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Offline sharif

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Re: testing rennet?
« Reply #1 on: March 30, 2013, 09:22:31 AM »
Hi Salilah,

I had the same problem yesterday, the difference I used rennet tablets instead but diidnt work
Looking at some reviews, its been said that I might over heated the milk!!!! but not sure the accuracy of it

Offline Salilah

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Re: testing rennet?
« Reply #2 on: March 30, 2013, 12:15:12 PM »
Hi Sharif
My latest was slightly higher than recipe i.e. 38C instead of 32C - but I hope that would not have made the difference?


Offline BobE102330

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Re: testing rennet?
« Reply #3 on: March 30, 2013, 12:45:44 PM »
Rennets vary in strength, and are sensitive to storage.  Assuming that yours has been stored properly, are you acidifying the milk properly before adding rennet?  Most of the time your cultures need time to work before the milk is acidified enough for rennet to work. 

Why not test using 1 or 2 liter batches, heat, add culture, let it work, then rennet at 2-4 times the recommended amount.  If that works in a reasonable time, then you can adjust the amounts you use.  If not, I'd ask for a replacement.  The rennet I have says use 1 tsp to set 2 gallons, but I find I need to use only 3/4 tsp for 3.5-4 gallons of milk to get flocculation in 15 minutes. 

As you've discovered, "expired" rennet doesn't immediately stop working, you may just have to use a bit more to get the flocculation time you are used to.  I can't comment on whether that affects the taste of the cheese.

Offline Salilah

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Re: testing rennet?
« Reply #4 on: March 31, 2013, 03:04:39 AM »
Hi BobE - thanks for the message!
Yes I think I'm acidifying - the camembert style recipe says add culture (and PC and Geo) to warmed milk, leave for 5m, mix thoroughly, leave for 45m then rennet
The lactic recipe doesn't suggest this resting time, but is left 24h after rennet to acidify - and I've checked pH for this one (though not for the camembert as the recipe says I should see a drop of 0.05 and I only have little paper tabs, so can't see this level of difference!)

Thanks re the idea of the higher amount and then adjust down - I'll see what happens (PS my normal batches are 2 litres!!)

cheers
S


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